[release-1.8] Use ubuntu 20.04 for kind e2e tests (#13540)

* use ubuntu 20.04 for kind e2e tests

Signed-off-by: Paul S. Schweigert <[email protected]>

Github recently made the `ubuntu-latest` runner label refer to Ubuntu
22.04 (before it had been 20.04). 22.04 uses cgroups v2 by default,
whereas 20.04 was still using cgroups v1.

It seems that our cgroups conformance tests were written for cgroups
v1, as they fail when using cgroups v2 (tested on both Ubuntu 22.04
and Fedora 36).

As a short-term solution, this patch will keep running the e2e tests
on Ubuntu 20.04, until we have a chance to rewrite the conformance
tests to work with cgroups v2.

* check cgroup version

Signed-off-by: Paul S. Schweigert <[email protected]>

* actually run the tests on 20.04 with go 1.19

Signed-off-by: Paul S. Schweigert <[email protected]>

Signed-off-by: Paul S. Schweigert <[email protected]>
Co-authored-by: Paul S. Schweigert <[email protected]>

.github/workflows/kind-e2e.yaml

@@ -24,7 +24,7 @@ env:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
 
     steps:
     - uses: actions/checkout@v3
@@ -82,7 +82,7 @@ jobs:
   test:
     name: test
     needs: build
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     strategy:
       fail-fast: false # Keep running if one leg fails.
       matrix:
@@ -152,10 +152,10 @@ jobs:
       ENABLE_TLS: ${{ matrix.enable-tls || 0 }}
 
     steps:
-    - name: Set up Go 1.18.x
+    - name: Set up Go 1.19.x
       uses: actions/setup-go@v3
       with:
-        go-version: 1.18.x
+        go-version: 1.19.x
 
     - uses: actions/cache@v3
       with: