Create msbuild48.yml

add github test action

.github/workflows/msbuild48.yml

@@ -0,0 +1,20 @@
+name: .msbuild48
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+    - name: preBuild
+      run: bash ${GITHUB_WORKSPACE}/runprebuild48.sh
+    - name: Build
+      run: msbuild /p:Configuration=Release OpenMetaverse.sln
+