Build native on Ubuntu 20.04 instead of latest 22.04 (re. #1072).

This MAY (?) help re. libc.so.6 (GLIBC_2.34) for
#1072.

Author: vorburger

.github/workflows/ci.yml

@@ -86,7 +86,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
+        # Use "oldest" available ubuntu-* instead of -latest,
+        # see https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners/about-github-hosted-runners#standard-github-hosted-runners-for-public-repositories;
+        # due to https://github.com/google/google-java-format/issues/1072.
+        os: [ubuntu-20.04, macos-latest, windows-latest]
     runs-on: ${{ matrix.os }}
     continue-on-error: true
     steps:

.github/workflows/release.yml

@@ -86,7 +86,10 @@ jobs:
     needs: build-maven-jars
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
+        # Use "oldest" available ubuntu-* instead of -latest,
+        # see https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners/about-github-hosted-runners#standard-github-hosted-runners-for-public-repositories;
+        # due to https://github.com/google/google-java-format/issues/1072.
+        os: [ubuntu-20.04, macos-latest, windows-latest]
     env:
       SUFFIX: ${{fromJson('{"ubuntu-latest":"linux-x86-64", "macos-latest":"darwin-arm64", "windows-latest":"windows-x86-64"}')[matrix.os]}}
       EXTENSION: ${{ matrix.os == 'windows-latest' && '.exe' || '' }}