Script to help check package compatibility

Sample usage:

checkpackagecompatibility.sh Google.Cloud.Storage.V1 2.3.0

This is a short term measure until we improve the compatibility checker itself, but it'll make validating autosynth PRs simpler.

checkpackagecompatibility.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+
+set -e
+
+if [[ -z "$1" || -z "$2" ]]
+then
+  echo Please specify the API name and the NuGet package version
+  exit 1
+fi
+
+# Fetch the package from NuGet and unzip it
+rm -rf tmp
+mkdir tmp
+cd tmp
+curl -sSL https://www.nuget.org/api/v2/package/$1/$2 --output tmp.zip
+unzip -q tmp.zip
+cd ..
+
+# Build the current source code
+./build.sh $1
+
+# Run the comparison tool
+
+old_dll=tmp/lib/netstandard1.*/$1.dll
+new_dll=apis/$1/$1/bin/Release/netstandard1.*/$1.dll
+dotnet run -p tools/Google.Cloud.Tools.VersionCompat -- $old_dll $new_dll