* Update GH workflows to run on ubuntu-latest (#2466)

Especially with ubuntu-18.04 deprecated

https://github.blog/changelog/2022-08-09-github-actions-ubuntu-22-04-is-now-generally-available-on-github-hosted-runners/

.github/workflows/build.yml

@@ -15,7 +15,7 @@ jobs:
         runtime: [ linux-x64, linux-arm64, win-x64, osx-x64 ]
         include:
         - runtime: linux-x64
-          os: ubuntu-18.04
+          os: ubuntu-latest
 
         - runtime: linux-arm64
           os: ubuntu-latest

.github/workflows/linter.yml

@@ -13,7 +13,7 @@ jobs:
   # This workflow contains a single job called "build"
   lint:
     # The type of runner that the job will run on
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps: