chore(java): bump com.uber.nullaway:nullaway from 0.12.3 to 0.12.4 in /java (apache#2572)

Bumps [com.uber.nullaway:nullaway](https://github.com/uber/NullAway)
from 0.12.3 to 0.12.4.

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

Author: dependabot[bot]

java/pom.xml

@@ -299,7 +299,7 @@
                 <path>
                   <groupId>com.uber.nullaway</groupId>
                   <artifactId>nullaway</artifactId>
-                  <version>0.12.3</version>
+                  <version>0.12.4</version>
                 </path>
                 <path>
                   <groupId>org.checkerframework</groupId>