Update rails version to 6.1.4

We'd like to use rails 6.1.4 in debian, but this results in the following error during db migration from gitlab 13.12.9 to 14.0.10 as well as user creation in fresh installed 14.0.10

ArgumentError: wrong number of arguments (given 0, expected 1)
/usr/share/gitlab/config/initializers/postgresql_cte.rb:99:in 
`build_arel'

More details here https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=993901

We could switch back to rails 6.1.3.2 as a last resort option, but it'd be nice to be able to use rails 6.1.4 as we will need to move to this version eventually.