Bump ubuntu to latest

Author: alpeb

.github/workflows/actions.yml

@@ -11,7 +11,7 @@ permissions:
 
 jobs:
   actionlint:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     timeout-minutes: 10
     steps:
       - uses: linkerd/dev/actions/setup-tools@v45

.github/workflows/integration.yml

@@ -8,7 +8,7 @@ permissions:
 
 jobs:
   test:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     timeout-minutes: 20
     steps:
     - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683

.github/workflows/release.yml

@@ -29,7 +29,7 @@ jobs:
 
   docker-build:
     needs: [tag]
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     permissions:
       packages: write
       id-token: write # needed for signing the images with GitHub OIDC Token