Try using ubuntu-20.04 for workflows

Using an older Ubuntu will maintain compatibility with a larger range of Operating Systems

.github/workflows/build-plugin.yml

@@ -13,7 +13,7 @@ jobs:
 
   modify-plugin-version:
     name: Modify plugin version
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v3
       - uses: actions/cache@v3
@@ -32,7 +32,7 @@ jobs:
   build:
     name: ${{ matrix.platform }}
     needs: modify-plugin-version
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     container:
       image: ghcr.io/qno/rack-plugin-toolchain-win-linux
       options: --user root
@@ -100,7 +100,7 @@ jobs:
     # only create a release if a tag was created that is called e.g. v1.2.3
     # see also https://vcvrack.com/manual/Manifest#version
     if: startsWith(github.ref, 'refs/tags/v')
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     needs:  [build, build-mac]
     steps:
       - uses: actions/checkout@v3