GitHub actions: Ubuntu 22.04

Use the most recent available GitHub runners (which is currently in
public beta). For Ubuntu we now have coverage of 18.04, 20.04, 22.04.

Author: tautschnig

.github/workflows/pull-request-checks.yaml

@@ -69,8 +69,8 @@ jobs:
           env PATH=$PATH:`pwd`/src/solvers make -C regression/cbmc test-cprover-smt2
           make -C jbmc/regression test-parallel JOBS=2
 
-  check-ubuntu-20_04-make-clang:
-    runs-on: ubuntu-20.04
+  check-ubuntu-22_04-make-clang:
+    runs-on: ubuntu-22.04
     env:
       CC: "ccache /usr/bin/clang"
       CXX: "ccache /usr/bin/clang++"
@@ -85,7 +85,7 @@ jobs:
           DEBIAN_FRONTEND: noninteractive
         run: |
           sudo apt-get update
-          sudo apt-get install --no-install-recommends -yq clang-10 clang++-10 gdb maven jq flex bison libxml2-utils cpanminus ccache z3
+          sudo apt-get install --no-install-recommends -yq clang-14 clang++-14 gdb maven jq flex bison libxml2-utils cpanminus ccache z3 python2
           make -C src minisat2-download
           cpanm Thread::Pool::Simple
       - name: Confirm z3 solver is available and log the version installed
@@ -100,10 +100,10 @@ jobs:
         uses: actions/cache@v2
         with:
           path: .ccache
-          key: ${{ runner.os }}-20.04-make-clang-${{ github.ref }}-${{ github.sha }}-PR
+          key: ${{ runner.os }}-22.04-make-clang-${{ github.ref }}-${{ github.sha }}-PR
           restore-keys: |
-            ${{ runner.os }}-20.04-make-clang-${{ github.ref }}
-            ${{ runner.os }}-20.04-make-clang
+            ${{ runner.os }}-22.04-make-clang-${{ github.ref }}
+            ${{ runner.os }}-22.04-make-clang
       - name: ccache environment
         run: |
           echo "CCACHE_BASEDIR=$PWD" >> $GITHUB_ENV