.github/workflows: Use Ubuntu 22.04

This simplifies the testing matrix and allows us to test with the
minimum required LTTng version without needing to deal with the flaky
PPA setup on Ubuntu 20.04.

Signed-off-by: Darryl Abbate <[email protected]>

.github/workflows/pr-ci.yml

@@ -23,8 +23,6 @@ env:
     sparse
     valgrind
     wget
-  APT_REPOS: >-
-    ppa:lttng/ppa
   OFI_PROVIDER_FLAGS: >-
     --enable-efa=$PWD/rdma-core/build
     --enable-mrail
@@ -44,7 +42,6 @@ jobs:
     strategy:
       matrix:
         os:
-          - ubuntu-20.04
           - ubuntu-22.04
         cc:
           - gcc
@@ -53,7 +50,6 @@ jobs:
     steps:
       - name: Install dependencies (Linux)
         run: |
-          sudo apt-add-repository ${{ env.APT_REPOS }}
           sudo apt-get update
           sudo apt-get install -y ${{ env.APT_PACKAGES }}
       - uses: actions/checkout@v4
@@ -75,11 +71,10 @@ jobs:
           name: ${{ matrix.os }}-${{ matrix.cc }}-config.log
           path: config.log
   hmem:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
       - name: Install dependencies (Linux)
         run: |
-          sudo apt-add-repository ${{ env.APT_REPOS }}
           sudo apt-get update
           sudo apt-get install -y ${{ env.APT_PACKAGES }}
       - name: Install CUDA