CI: install a newer java on opensuse

They do not appear to have 15 in their repos anymore, and no traces can
be found of it in the history, as usual. They do have 11, 17, and 20, so
choose one randomly and hope it doesn't keep changing value.

ci/ciimage/opensuse/install.sh

@@ -9,7 +9,7 @@ pkgs=(
   ninja make git autoconf automake patch libjpeg-devel
   elfutils gcc gcc-c++ gcc-fortran gcc-objc gcc-obj-c++ vala rust bison flex curl lcov
   mono-core gtkmm3-devel gtest gmock protobuf-devel wxGTK3-3_2-devel gobject-introspection-devel
-  itstool gtk3-devel java-15-openjdk-devel gtk-doc llvm-devel clang-devel libSDL2-devel graphviz-devel zlib-devel zlib-devel-static
+  itstool gtk3-devel java-20-openjdk-devel gtk-doc llvm-devel clang-devel libSDL2-devel graphviz-devel zlib-devel zlib-devel-static
   #hdf5-devel netcdf-devel libscalapack2-openmpi3-devel libscalapack2-gnu-openmpi3-hpc-devel openmpi3-devel
   doxygen vulkan-devel vulkan-validationlayers openssh mercurial gtk-sharp3-complete gtk-sharp2-complete libpcap-devel libgpgme-devel
   libqt5-qtbase-devel libqt5-qttools-devel libqt5-linguist libqt5-qtbase-private-headers-devel