Revert "Merge branch 'fix-rspec_profiling-establish_connection-string-deprecation' into 'master'

This reverts commit 7041de94.

config/initializers/rspec_profiling.rb

 module RspecProfilingExt
   module PSQL
     def establish_connection
-      ::RspecProfiling::Collectors::PSQL::Result.establish_connection(ENV['RSPEC_PROFILING_POSTGRES_URL'].to_sym)
+      ::RspecProfiling::Collectors::PSQL::Result.establish_connection(ENV['RSPEC_PROFILING_POSTGRES_URL'])
     end
   end