bump CI to ubuntu-22.04 and cache@v4

Author: folkertdev

.github/workflows/internal-testsuite.yml

@@ -13,9 +13,9 @@ on:
 # A workflow run is made up of one or more jobs that can run sequentially or in parallel
 jobs:
   # This workflow contains a single job called "build"
-  build-on-ubuntu-2004:
+  build-on-ubuntu-2204:
     # The type of runner that the job will run on
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
@@ -33,7 +33,7 @@ jobs:
         submodules: true
 
     - name: Cache Rust toolchain
-      uses: actions/cache@v2
+      uses: actions/cache@v4
       with:
         path: |
           ~/.rustup/toolchains
@@ -42,7 +42,7 @@ jobs:
         key: ${{ runner.os }}-rust-toolchain-${{ hashFiles('rust-toolchain') }}
 
     - name: Cache Rust artifacts
-      uses: actions/cache@v2
+      uses: actions/cache@v4
       with:
         path: |
           ~/.cargo/registry
@@ -52,7 +52,7 @@ jobs:
         key: ${{ runner.os }}-${{ hashFiles('**/Cargo.lock', '**/c2rust-ast-exporter/**/CMakeLists.txt', '**/examples/**/CMakeLists.txt') }}
 
     - name: Cache Python - pip
-      uses: actions/cache@v2
+      uses: actions/cache@v4
       with:
         path: ~/.cache/pip
         key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}