Cast ENV['RSPEC_PROFILING_POSTGRES_URL'] to symbol in establish_connection...

Cast ENV['RSPEC_PROFILING_POSTGRES_URL'] to symbol in establish_connection call of rspec_profiling.rb

Former-commit-id: e6f008bb

config/initializers/rspec_profiling.rb

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