Add workflow for apt-get release

This adds support for releasing to Ubuntu repositories hosted
at http://packages.microsoft.com/ (hosting location for Microsoft's
official apt/yum repos). This allows users to install via apt-get on
Hirsute/Bionic. Details to configure appropriate repos can be found
here:

https://docs.microsoft.com/en-us/windows-server/administration/Linux-Package-Repository-for-Microsoft-Software).

.github/workflows/release-apt-get.yml

@@ -0,0 +1,92 @@
+name: "release-apt-get"
+on:
+  release:
+    types: [released]
+
+  workflow_dispatch:
+    inputs:
+      release:
+        description: 'Release Id'
+        required: true
+        default: 'latest'
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - uses: azure/login@v1
+        with:
+          creds: ${{ secrets.AZURE_CREDENTIALS }}
+
+      - name: "Download Repo Client"
+        env:
+          AZ_SUB: ${{ secrets.AZURE_SUBSCRIPTION }}
+        run: |
+          az storage blob download --subscription  "$AZ_SUB" --account-name gitcitoolstore -c tools -n azure-repoapi-client_2.0.1_amd64.deb -f repoclient.deb --auth-mode login
+
+      - name: "Install Repo Client"
+        run: |
+          sudo apt-get install python3-adal --yes
+          sudo dpkg -i repoclient.deb
+          rm repoclient.deb
+
+      - name: "Configure Repo Client"
+        uses: actions/github-script@v3
+        env:
+          AZURE_AAD_ID: ${{ secrets.AZURE_AAD_ID }}
+          AAD_CLIENT_SECRET: ${{ secrets.AAD_CLIENT_SECRET }}
+        with:
+          script: |
+            for (const key of ['AZURE_AAD_ID', 'AAD_CLIENT_SECRET']) {
+              if (!process.env[key]) throw new Error(`Required env var ${key} is missing!`)
+            }
+            const config = {
+              AADResource: 'https://microsoft.onmicrosoft.com/945999e9-da09-4b5b-878f-b66c414602c0',
+              AADTenant: '72f988bf-86f1-41af-91ab-2d7cd011db47',
+              AADAuthorityUrl: 'https://login.microsoftonline.com',
+              server: 'azure-apt-cat.cloudapp.net',
+              port: '443',
+              AADClientId: process.env.AZURE_AAD_ID,
+              AADClientSecret: process.env.AAD_CLIENT_SECRET,
+              repositoryId: ''
+            }
+            const fs = require('fs')
+            fs.writeFileSync('config.json', JSON.stringify(config, null, 2))
+
+      - name: "Get Release Asset"
+        id: get-asset
+        env:
+          RELEASE: ${{ github.event.inputs.release }}
+        uses: actions/github-script@v3
+        with:
+          github-token: ${{secrets.GITHUB_TOKEN}}
+          script: |
+            const { data } = await github.repos.getRelease({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                release_id: process.env.RELEASE || 'latest'
+              })
+            const assets = data.assets.filter(asset => asset.name.endsWith('.deb'))
+            if (assets.length !== 1) {
+              throw new Error(`Unexpected number of .deb assets: ${assets.length}`)
+            }
+            const fs = require('fs')
+            const buffer = await github.repos.getReleaseAsset({
+                headers: {
+                  accept: 'application/octet-stream'
+                },
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                asset_id: assets[0].id
+              })
+            console.log(buffer)
+            fs.writeFileSync(assets[0].name, Buffer.from(buffer.data))
+            core.setOutput('name', assets[0].name)
+
+      - name: "Publish to apt feed"
+        env:
+          RELEASE: ${{ github.event.inputs.release }}
+        run: |
+          repoclient -v v3 -c config.json package add --check --wait 300 ${{steps.get-asset.outputs.name}} -r ${{ secrets.HIRSUTE_REPO_ID }}