unable to install pldebugger

I am in a process of upgrading postgres 12 to 13 on ubuntu. When I am running the test getting error could not load library "$libdir/plugin_debugger": ERROR:  could not load library "/usr/lib/postgresql/13/lib/plugin_debugger.so": /usr/lib/postgresql/13/lib/plugin_debugger.so: undefined symbol: elog_finish

When I am trying to install pldebugger from https://git.postgresql.org/git/pldebugger.git getting that repository not found. Could you please help me to fix this issue.
--