widen glibc compatibility by running on older ubuntu version

Code built on glibc version X only works on X>=1, not on older
version.

For example, if one tries to use the latest release with a project
using `ubuntu-22.04` GitHub runners one will get an error like:

```
./protoc-gen-grpc-python-linux-x86_64-v1.73.1:
/lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.38' not
found (required by ./protoc-gen-grpc-python-linux-x86_64-v1.73.1)
```

Compiling on an older but still supported runner will broaden the
range of distributions that can use this binary.

Author: cburroughs

.github/workflows/build-and-release.yml

@@ -20,7 +20,7 @@ on:
 
 jobs:
   prepare:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-22.04
     outputs:
       matrix: ${{ steps.set-matrix.outputs.matrix }}
       should_release: ${{ steps.check-release.outputs.should_release }}

.github/workflows/lint.yml

@@ -6,7 +6,7 @@ on:
 jobs:
   shellcheck:
     name: ShellCheck
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-22.04
     steps:
       - name: Checkout repository
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
@@ -17,7 +17,7 @@ jobs:
 
   ruff:
     name: Ruff
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-22.04
     steps:
       - name: Checkout repository
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4

.github/workflows/release-drafter.yml

@@ -15,7 +15,7 @@ jobs:
     permissions:
       contents: write
       pull-requests: write
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-22.04
     steps:
       - uses: release-drafter/release-drafter@b1476f6e6eb133afa41ed8589daba6dc69b4d3f5 # v6
         env:

.github/workflows/release.yml

@@ -10,7 +10,7 @@ on:
 
 jobs:
   release:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-22.04
     permissions:
       contents: write
 

grpc-versions.yaml

@@ -40,11 +40,11 @@ versions:
   active: false
 platforms:
 - name: linux-x86_64
-  os: ubuntu-24.04
+  os: ubuntu-22.04
   bazel_config: --config=linux
   artifact_name: protoc-gen-grpc-python-linux-x86_64
 - name: linux-aarch64
-  os: ubuntu-24.04-arm
+  os: ubuntu-22.04-arm
   bazel_config: --config=linux
   artifact_name: protoc-gen-grpc-python-linux-aarch64
 - name: macos-universal