Run StoneWork CI tests on Ubuntu 20.04 (#111)

* Fail CI job when enabling VRF kernel module fails
* Run CI tests on Ubuntu 20.04

Signed-off-by: Peter Motičák <peter.moticak@pantheon.tech>

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ on:
 
 jobs:
   check:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v3
@@ -22,7 +22,7 @@ jobs:
           git diff --name-only --exit-code go.mod || ( git diff && echo "Run go tidy to update go.mod" && false )
 
   build:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v3
@@ -34,14 +34,14 @@ jobs:
           go build -v ./...
 
   test:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v3
       - name: "Enable VRF kernel module"
         run: |
           sudo apt-get update && \
           sudo apt-get install -y linux-modules-extra-$(uname -r) && \
-          sudo modprobe -v vrf || echo >&2 "FAILURE"
+          sudo modprobe -v vrf || ( echo >&2 "FAILURE"; false )
       - name: "Build images"
         run: make images
       - name: "Run Tests"