deps: Bump `com_github_bufbuild_buf` -> 1.4.0 (#21473)

Fix #20937

Signed-off-by: Ryan Northey <ryan@synca.io>

Mirrored from https://github.com/envoyproxy/envoy @ 13d855e62e40a42790db2bce373b8f7f9088a0b5

bazel/repository_locations.bzl

@@ -111,11 +111,11 @@ REPOSITORY_LOCATIONS_SPEC = dict(
         project_name = "buf",
         project_desc = "A new way of working with Protocol Buffers.",  # Used for breaking change detection in API protobufs
         project_url = "https://buf.build",
-        version = "1.3.1",
-        sha256 = "308283e8fe11e2be738fbe1b47d59220eef519c8f6fdf390a4f8d86b6288795e",
+        version = "1.4.0",
+        sha256 = "826ad701db09805eb425723ad3ea0c13ce7ca8353d6a1fb473399db915dafdf9",
         strip_prefix = "buf",
         urls = ["https://github.com/bufbuild/buf/releases/download/v{version}/buf-Linux-x86_64.tar.gz"],
-        release_date = "2022-03-31",
+        release_date = "2022-04-21",
         use_category = ["api"],
         tags = ["manual"],
     ),