Release process: add anchor so I can de-duplicate info in whisperback.git.

wiki/src/contribute/release_process.mdwn

@@ -173,6 +173,8 @@ The patterns+settings file is stored as a SQLite text dump in
            config/chroot_local-includes/usr/share/tails/ublock-origin/ublock0.dump \
         && rm ublock0.sqlite
 
+<a id="upgrade-custom-debs"></a>
+
 Upgrade bundled binary Debian packages
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