Bump com.google.protobuf:protoc from 3.23.1 to 3.23.4 (#152)

Bumps [com.google.protobuf:protoc](https://github.com/protocolbuffers/protobuf) from 3.23.1 to 3.23.4.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/protobuf_release.bzl)
- [Commits](protocolbuffers/protobuf@v3.23.1...v3.23.4)

---
updated-dependencies:
- dependency-name: com.google.protobuf:protoc
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Max Lambrecht <[email protected]>

java-spiffe-core/build.gradle

@@ -50,7 +50,7 @@ task integrationTest(type: Test) {
 
 protobuf {
     protoc {
-        artifact = 'com.google.protobuf:protoc:3.23.1'
+        artifact = 'com.google.protobuf:protoc:3.23.4'
     }
     plugins {
         grpc {