Bump com.signalfx.public:signalfx-protoc (#4523)

Bumps [com.signalfx.public:signalfx-protoc](https://github.com/signalfx/signalfx-java) from 1.0.39 to 1.0.40.
- [Release notes](https://github.com/signalfx/signalfx-java/releases)
- [Commits](signalfx/signalfx-java@v1.0.39...v1.0.40)

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

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

internal/signalfx-agent/bundle/java/jmx/pom.xml

@@ -30,7 +30,7 @@
         <dependency>
             <groupId>com.signalfx.public</groupId>
             <artifactId>signalfx-protoc</artifactId>
-            <version>1.0.39</version>
+            <version>1.0.40</version>
         </dependency>
         <dependency>
             <groupId>com.google.guava</groupId>