feature(grpc): Add engine version to version svc

Fixes #1269

Add two new fields in the version service for falco's engine version and
the checksum of all of the fields it understands.

This will require rebuilding/re-releasing all the clients.

Signed-off-by: Spencer Krum <nibz@spencerkrum.com>

userspace/falco/grpc_server_impl.cpp

@@ -15,6 +15,7 @@ limitations under the License.
 */
 
 #include "config_falco.h"
+#include "falco_engine_version.h"
 #include "grpc_server_impl.h"
 #include "grpc_queue.h"
 #include "logger.h"
@@ -75,6 +76,9 @@ void falco::grpc::server_impl::version(const context& ctx, const version::reques
 	auto& version = *res.mutable_version();
 	version = FALCO_VERSION;
 
+    res.set_engine_version(FALCO_ENGINE_VERSION);
+	res.set_engine_fields_checksum(FALCO_FIELDS_CHECKSUM); 
+
 	res.set_major(FALCO_VERSION_MAJOR);
 	res.set_minor(FALCO_VERSION_MINOR);
 	res.set_patch(FALCO_VERSION_PATCH);

userspace/falco/version.proto

@@ -36,10 +36,14 @@ message request
 // its parts as per semver 2.0 specification (https://semver.org).
 message response
 {
+// falco version
   string version = 1;
   uint32 major = 2;
   uint32 minor = 3;
   uint32 patch = 4;
   string prerelease = 5;
   string build = 6;
-}
+// falco engine version
+  uint32 engine_version = 7;
+  string engine_fields_checksum = 8;
+}