Run build on multiple platforms

Author: ejsmith

.github/workflows/build.yml

@@ -4,7 +4,10 @@ env:
   DOTNET_CLI_TELEMETRY_OPTOUT: 1
 jobs:
   build:
-    runs-on: windows-latest
+    runs-on: ${{matrix.os}}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macOS-latest]
     steps:
     - name: Checkout
       uses: actions/checkout@v1
@@ -19,7 +22,7 @@ jobs:
     - name: Build Version
       shell: bash
       run: |
-        dotnet tool install --global minver-cli --version 2.3.0
+        dotnet tool install --global minver-cli --version 2.3.1
         version=$(minver --tag-prefix v)
         echo "::set-env name=MINVERVERSIONOVERRIDE::$version"
     - name: Build
@@ -34,7 +37,7 @@ jobs:
       run: dotnet tool install gpr -g
     - name: Publish CI Packages
       shell: bash
-      if: github.event_name != 'pull_request'
+      if: github.event_name != 'pull_request' && matrix.os == 'ubuntu-latest'
       run: |
         for package in $(find -name "*.nupkg" | grep "minver" -v); do
           echo "${0##*/}": Pushing $package...
@@ -47,7 +50,7 @@ jobs:
         done
     - name: Publish Release Packages
       shell: bash
-      if: startsWith(github.ref, 'refs/tags/v')
+      if: startsWith(github.ref, 'refs/tags/v') && matrix.os == 'ubuntu-latest'
       run: |
         for package in $(find -name "*.nupkg" | grep "minver" -v); do
           echo "${0##*/}": Pushing $package...