chore: Replace deprecated ubuntu runner (#792)

Author: teeohhem

.github/workflows/main.yml

@@ -10,7 +10,7 @@ concurrency:
 jobs:
   lint:
     timeout-minutes: 8
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
       - name: Checkout
         uses: actions/checkout@v2
@@ -32,7 +32,7 @@ jobs:
         run: make ci-lint
   unit:
     timeout-minutes: 8
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
       - name: Checkout
         uses: actions/checkout@v2
@@ -46,7 +46,7 @@ jobs:
         run: make ci-unit
   integration:
     timeout-minutes: 8
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
       - name: Checkout
         uses: actions/checkout@v2