Update min PHP testing version from PHP 7.4 to 8.1

- PHP 7.4 and 8.0 has been EOL
- See go/drop-php-8.0 for more details

examples/php/echo/apache.Dockerfile

@@ -18,7 +18,7 @@ FROM composer:1.8.6 as composer
 FROM grpc-php/base as grpc-base
 
 
-FROM php:7.4-apache-buster
+FROM php:8.1-apache-buster
 
 RUN apt-get -qq update && apt-get -qq install -y git
 

examples/php/echo/base.Dockerfile

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM php:7.4-buster
+FROM php:8.1-buster
 
 RUN apt-get -qq update && apt-get -qq install -y \
   autoconf automake cmake curl git libtool \

examples/php/echo/cli.Dockerfile

@@ -18,7 +18,7 @@ FROM composer:1.8.6 as composer
 FROM grpc-php/base as grpc-base
 
 
-FROM php:7.4-buster
+FROM php:8.1-buster
 
 RUN apt-get -qq update && apt-get -qq install -y git
 

examples/php/echo/fpm.Dockerfile

@@ -18,7 +18,7 @@ FROM composer:1.8.6 as composer
 FROM grpc-php/base as grpc-base
 
 
-FROM php:7.4-fpm-buster
+FROM php:8.1-fpm-buster
 
 RUN apt-get -qq update && apt-get -qq install -y git
 

src/php/docker/alpine/Dockerfile

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM php:7.4-alpine3.15
+FROM php:8.1-alpine3.15
 
 RUN apk add autoconf g++ make zlib-dev git bash wget linux-headers
 

src/php/docker/grpc-ext/Dockerfile

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM php:7.4-buster
+FROM php:8.1-buster
 
 RUN apt-get -qq update && apt-get -qq -y upgrade && apt-get -qq install -y \
   autoconf automake git libtool pkg-config \

src/php/docker/grpc-src/Dockerfile

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM php:7.4-buster
+FROM php:8.1-buster
 
 RUN apt-get -qq update && apt-get -qq -y upgrade && apt-get -qq install -y \
   autoconf automake git libtool pkg-config \

src/php/docker/i386/Dockerfile

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM i386/php:7.4
+FROM i386/php:8.1
 
 RUN apt-get -qq update && apt-get -qq -y upgrade && apt-get -qq install -y \
   autoconf automake git libtool pkg-config \

src/php/docker/php-src/Dockerfile

@@ -34,7 +34,7 @@ ARG MAKEFLAGS=-j8
 
 RUN git clone https://github.com/php/php-src .
 
-RUN git checkout php-7.4.33 && \
+RUN git checkout php-8.1.27 && \
   ./buildconf --force && \
   ./configure --build=x86_64-linux-gnu --enable-option-checking=fatal \
     --enable-debug --enable-pcntl \

src/php/docker/php-zts/Dockerfile

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM php:7.4-zts-buster
+FROM php:8.1-zts-buster
 
 RUN apt-get -qq update && apt-get -qq -y upgrade && apt-get -qq install -y \
   autoconf automake git libtool pkg-config \

templates/src/php/docker/php-src/Dockerfile.template

@@ -33,7 +33,7 @@
 
   RUN git clone https://github.com/php/php-src .
 
-  RUN git checkout php-7.4.33 && ${'\\'}
+  RUN git checkout php-8.1.27 && ${'\\'}
     ./buildconf --force && ${'\\'}
     ./configure --build=x86_64-linux-gnu --enable-option-checking=fatal ${'\\'}
       --enable-debug --enable-pcntl ${'\\'}

tools/buildgen/plugins/expand_version.py

@@ -106,7 +106,7 @@ class Version:
         return "%d.%d.%d" % (self.major, self.minor, self.patch)
 
     def php_current_version(self):
-        return "7.4"
+        return "8.1"
 
     def php_debian_version(self):
         return "buster"

tools/internal_ci/helper_scripts/prepare_build_macos_rc

@@ -196,16 +196,15 @@ fi
 
 if [ "${PREPARE_BUILD_INSTALL_DEPS_PHP}" == "true" ]
 then
-  # php7.4 should already be installed on kokoro monterey image, so this should be instantaneous.
-  time brew install php@7.4 || true
-  export LDFLAGS="-L/usr/local/opt/php@7.4/lib ${LDFLAGS}"
-  export CPPFLAGS="-I/usr/local/opt/php@7.4/include ${CPPFLAGS}"
-  export PATH="/usr/local/opt/php@7.4/bin:/usr/local/opt/php@7.4/sbin:${PATH}"
+  time brew install php@8.1 || true
+  export LDFLAGS="-L/usr/local/opt/php@8.1/lib ${LDFLAGS}"
+  export CPPFLAGS="-I/usr/local/opt/php@8.1/include ${CPPFLAGS}"
+  export PATH="/usr/local/opt/php@8.1/bin:/usr/local/opt/php@8.1/sbin:${PATH}"
 
-  # the exit code from "brew install php@7.4" is useless
+  # the exit code from "brew install php@8.1" is useless
   # so instead we check if PHP was indeed installed successfully.
   # Failing early is better than cryptic errors later in the build process.
-  /usr/local/opt/php@7.4/bin/php --version
+  /usr/local/opt/php@8.1/bin/php --version
 
   # Workaround for https://github.com/Homebrew/homebrew-core/issues/41081
   mkdir -p /usr/local/lib/php/pecl