Added 'sketch_path' to build properties (#2372)

Author: cmaglie

Diff for: arduino/builder/builder.go

@@ -131,7 +131,9 @@ func NewBuilder(
 	if boardBuildProperties != nil {
 		buildProperties.Merge(boardBuildProperties)
 	}
-
+	if sk != nil {
+		buildProperties.SetPath("sketch_path", sk.FullPath)
+	}
 	if buildPath != nil {
 		buildProperties.SetPath("build.path", buildPath)
 	}

Diff for: internal/integrationtest/compile_3/compile_show_properties_test.go

@@ -48,6 +48,7 @@ func TestCompileShowProperties(t *testing.T) {
 	require.NoError(t, err, "Output must be a clean property list")
 	require.Empty(t, stderr)
 	require.True(t, props.ContainsKey("archive_file_path"))
+	require.True(t, props.ContainsKey("sketch_path"))
 	require.NotContains(t, props.Get("archive_file_path"), "{build.path}")
 
 	// Test --show-properties --format JSON output is clean