Improve version handling for eclipse plugin

[cristatus]

Use same versions for plugin as google-java-format and
strip versions from copied jar to avoid updating build.properties
and MANIFEST.MF.

[cristatus]

I have just built the latest plugin for eclipse from this branch,

google-java-format-eclipse-plugin-1.11.0.jar

Put the plugin jar inside the dropins folder.

If you are using eclipse with JDK-16 or later, add the following lines at the end of eclipse.ini:

--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED
--add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED
--add-exports=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED
--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED
--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED

[cushon]

Thanks @cristatus!

I followed the updated instructions to build the plugin, and uploaded a copy to the release page for 1.11.0: https://github.com/google/google-java-format/releases/tag/v1.11.0

[cristatus]

Thanks @cushon!