Merge pull request microsoft#328: Adding winget workflow

Adding a shiny new workflow to publish releases to winget! 🥳

I validated this workflow locally by successfully opening a [PR](https://github.com/ldennington/winget-playground/pull/4) against my winget-playground repo and running `winget validate` to ensure the generated manifest adheres to winget's required schema. Any feedback on the fields I've included (\*cough\* `ShortDescription:` \*cough\*) or suggestions for additional fields/values are welcome!

.github/workflows/release-winget.yml

@@ -0,0 +1,23 @@
+name: "release-winget"
+on:
+  release:
+    types: [released]
+
+jobs:
+  release:
+    runs-on: windows-latest
+    steps:
+      - name: Publish manifest with winget-create
+        run: |
+          # Get correct release asset
+          $github = Get-Content '${{ github.event_path }}' | ConvertFrom-Json
+          $asset = $github.release.assets | Where-Object -Property name -match '64-bit.exe$'
+
+          # Remove 'v' and 'vfs' from the version
+          $github.release.tag_name -match '\d.*'
+          $version = $Matches[0] -replace ".vfs",""
+
+          # Download and run wingetcreate
+          Invoke-WebRequest https://aka.ms/wingetcreate/latest -OutFile wingetcreate.exe
+          .\wingetcreate.exe update Microsoft.Git -u $asset.browser_download_url -v $version -o manifests -t "${{ secrets.WINGET_TOKEN }}" -s
+        shell: powershell