Remove Gemfile.lock from template (facebook#33469)

Summary:
For the same reason we don't keep a yarn.lock or Podfile.lock, we shouldn't be keeping a Gemfile.lock in the template. The user will generate this on his own pulling in the current dependencies with the constraints in Gemfile. No need to lock to a specific version.

cc barbieri (author of facebook#32303)
cc ravirajn22 (for raising the issue)

[iOS] [Fixed] - Remove Gemfile.lock from template

Pull Request resolved: facebook#33469

Test Plan: no test plan

Reviewed By: javache

Differential Revision: D35074105

Pulled By: cortinico

fbshipit-source-id: 47d1b92329f1d55d4a0adbacbc7e5e45f9d957e0

scripts/update-ruby.sh

@@ -53,17 +53,15 @@ echo "$VERSION" > template/_ruby-version
 sed_i -e "s/^\(ruby '\)[^']*\('.*\)$/\1$VERSION\2/" Gemfile
 sed_i -e "s/^\(ruby '\)[^']*\('.*\)$/\1$VERSION\2/" template/Gemfile
 
-rm -f Gemfile.lock template/Gemfile.lock
+rm -f Gemfile.lock
 
 export BUNDLE_APP_CONFIG="$ROOT/.bundle"
 cp "$BUNDLE_APP_CONFIG/"* template/_bundle # sync!
 
 bundle lock
-(cd template && bundle lock)
 
 git add \
     .ruby-version \
     Gemfile \
     template/_ruby-version \
-    template/Gemfile \
-    template/Gemfile.lock
+    template/Gemfile