Switch from Ubuntu 20.04 LTS to 22.04 LTS for jobs (#1353)

Switch from Ubuntu 20.04 LTS to 22.04 LTS for build jobs "build", "test-sim" and "build-multilib".

Signed-off-by: Tommy Murphy <tommy_murphy@hotmail.com>

.github/workflows/build.yaml

@@ -50,7 +50,7 @@ jobs:
 
       - name: make report
         if: |
-          matrix.os == 'ubuntu-20.04'
+          matrix.os == 'ubuntu-22.04'
           && (matrix.mode == 'linux' || matrix.mode == 'newlib')
           && matrix.compiler == 'gcc'
         run: |
@@ -88,7 +88,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os:     [ubuntu-20.04]
+        os:     [ubuntu-22.04]
         mode:   [newlib]
         target: [rv64gc-lp64d]
         sim:    [spike]
@@ -121,7 +121,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os:     [ubuntu-20.04]
+        os:     [ubuntu-22.04]
         mode:   [newlib, linux]
         target: [rv64gc-lp64d]
     steps: