Use latest Ubuntu in CI.

Author: johnbillion

.github/workflows/deploy.yml

@@ -7,7 +7,7 @@ on:
 
 jobs:
   marketplaces:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
@@ -86,7 +86,7 @@ jobs:
 
   github:
     name: GitHub Milestones
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     steps:
     - name: Get next versions
       id: semvers

.github/workflows/test.yml

@@ -10,7 +10,7 @@ jobs:
   test:
     if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != github.repository
     name: Linter
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     steps:
     - name: Checkout repository
       uses: actions/checkout@v1