Updated ubuntu version for github workflows

Author: kompotkot

.github/workflows/build.yml

@@ -4,7 +4,7 @@ on: [pull_request]
 
 jobs:
   build:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-go@v2

.github/workflows/release.yml

@@ -9,7 +9,7 @@ on:
 
 jobs:
   create_release:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/create-release@v1
         id: create_release
@@ -25,7 +25,7 @@ jobs:
     outputs:
       upload_url: ${{ steps.create_release.outputs.upload_url }}
   upload_assets:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     needs: create_release
     strategy:
       fail-fast: true