Add code coverage to Makefile

Author: praeclarum

Makefile

@@ -26,3 +26,6 @@ basenuget: nuget/SQLite-net-base/SQLite-net-base.csproj $(SRC)
 
 sqlciphernuget: nuget/SQLite-net-sqlcipher/SQLite-net-sqlcipher.csproj $(SRC)
 	dotnet pack -c Release -o $(PACKAGES_OUT) $<
+
+codecoverage:
+	cd tests/SQLite.Tests && dotnet test /p:AltCover=true /p:AltCoverForce=true "/p:AltCoverTypeFilter=SQLite.Tests.*" && reportgenerator -reports:coverage.xml -targetdir:./CoverageReport