Merge pull request #725 from Xilinx/fix/GHA

Update GHA to use Ubuntu 20.04

.github/workflows/docker-image.yml

@@ -7,7 +7,7 @@ on:
 
 jobs:
   docker:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-20.04
     steps:
       -
         name: checkout

.github/workflows/quicktest-dev-pr.yml

@@ -11,7 +11,7 @@ jobs:
 
   test:
     name: Run quicktest on PR branch
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-20.04
 
     steps:
       - name: checkout