Bump more deps.

This is everything surfaced by a command like the one I used for some of our libraries, as in CL 348090041:

```
( for F in $(find -name pom.xml); do ( mvn org.codehaus.mojo:versions-maven-plugin:2.8.1:update-properties org.codehaus.mojo:versions-maven-plugin:2.8.1:use-latest-releases -f $F -DgenerateBackupPoms=false ); done )
```

Note that this covers *dependencies* but not *plugins*.

Fixes #206

COPYBARA_INTEGRATE_REVIEW=https://github.com/google/turbine/pull/206 from cpovirk:otherdeps be604ef180b627c918d25bcb26413caa022f2825
PiperOrigin-RevId: 424084225
diff --git a/pom.xml b/pom.xml
index e32fb8a..b8710b5 100644
--- a/pom.xml
+++ b/pom.xml
@@ -31,7 +31,7 @@
 
   <properties>
     <asm.version>9.2</asm.version>
-    <guava.version>30.0-jre</guava.version>
+    <guava.version>31.0.1-jre</guava.version>
     <errorprone.version>2.10.0</errorprone.version>
     <maven-javadoc-plugin.version>3.1.0</maven-javadoc-plugin.version>
     <maven-source-plugin.version>3.2.1</maven-source-plugin.version>
@@ -69,7 +69,7 @@
     <dependency>
       <groupId>com.google.protobuf</groupId>
       <artifactId>protobuf-java</artifactId>
-      <version>3.19.3</version>
+      <version>4.0.0-rc-2</version>
     </dependency>
     <dependency>
       <groupId>org.ow2.asm</groupId>