feat(ci): Split CI/CD configuration

`build` job was redundant for PRs and pushes to `master` branch, as `go build`
is run in the e2e job.

Linting jobs only need to be run for code changes, and were unnecessarily
extending CI duration for documentation changes.

Signed-off-by: Ben Reedy <breed808@breed808.com>

.github/workflows/release.yml

@@ -0,0 +1,102 @@
+name: Releases
+
+# Trigger on releases.
+on:
+  release:
+    types:
+      - published
+      - edited
+
+permissions:
+  contents: write
+  packages: write
+
+env:
+  PROMU_VER: 'v0.13.0'
+
+jobs:
+  build:
+    runs-on: windows-2022
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          # fetch-depth required for gitversion in `Build` step
+          fetch-depth: 0
+
+      - uses: actions/setup-go@v2
+        with:
+          go-version: '^1.17.5'
+
+      - name: Install Build deps
+        run: |
+          dotnet tool install --global GitVersion.Tool --version 5.*
+          go install "github.com/prometheus/promu@$($Env:PROMU_VER)"
+          go install github.com/josephspurrier/goversioninfo/cmd/goversioninfo@v1.4.0
+          # GOPATH\bin dir must be added to PATH else the `promu` and `goversioninfo` commands won't be found
+          echo "$(go env GOPATH)\bin" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
+
+      - name: Build
+        run: |
+          $ErrorActionPreference = "Stop"
+
+          dotnet-gitversion /output json /showvariable FullSemVer | Set-Content VERSION -PassThru
+          $Version = Get-Content VERSION
+          # Windows versioninfo resources need the file version by parts (but product version is free text)
+          $VersionParts = ($Version -replace '^v?([0-9\.]+).*$','$1').Split(".")
+          goversioninfo.exe -ver-major $VersionParts[0] -ver-minor $VersionParts[1] -ver-patch $VersionParts[2] -product-version $Version -platform-specific
+
+          make crossbuild
+          # '+' symbols are invalid characters in image tags
+          (Get-Content -Path VERSION) -replace '\+', '_' | Set-Content -Path VERSION
+          make build-all
+          # GH requires all files to have different names, so add version/arch to differentiate
+          foreach($Arch in "amd64", "arm64","386") {
+            Move-Item output\$Arch\windows_exporter.exe output\windows_exporter-$Version-$Arch.exe
+          }
+
+      - name: Upload Artifacts
+        uses: actions/upload-artifact@v2
+        with:
+          name: windows_exporter_binaries
+          path: output\windows_exporter-*.exe
+
+      - name: Build Release Artifacts
+        if: startsWith(github.ref, 'refs/tags/')
+        run: |
+          $ErrorActionPreference = "Stop"
+          $BuildVersion = Get-Content VERSION
+          $TagName = $env:GITHUB_REF -replace 'refs/tags/', ''
+          # The MSI version is not semver compliant, so just take the numerical parts
+          $MSIVersion = $TagName -replace '^v?([0-9\.]+).*$','$1'
+          foreach($Arch in "amd64", "arm64","386") {
+            Write-Verbose "Building windows_exporter $MSIVersion msi for $Arch"
+            .\installer\build.ps1 -PathToExecutable .\output\windows_exporter-$BuildVersion-$Arch.exe -Version $MSIVersion -Arch "$Arch"
+            Move-Item installer\Output\windows_exporter-$MSIVersion-$Arch.msi output\
+          }
+
+          promu checksum output\
+
+      - name: Login to GitHub container registry
+        if: ${{ github.event_name != 'pull_request' }}
+        uses: docker/login-action@v1
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Push Latest image
+        if: ${{ github.event_name != 'pull_request' }}
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          $Env:VERSION = 'latest'
+          make push-all
+
+      - name: Release
+        if: startsWith(github.ref, 'refs/tags/')
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          $TagName = $env:GITHUB_REF -replace 'refs/tags/', ''
+          Get-ChildItem -Path output\* -Include @('windows_exporter*.msi', 'windows_exporter*.exe', 'sha256sums.txt') | Foreach-Object {gh release upload $TagName $_}
+          make push-all