Update Ruby gemspec template

Loosen development dependencies for googleauth and signet.

grpc.gemspec

@@ -41,8 +41,8 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'rake-compiler-dock', '~> 0.5.1'
   s.add_development_dependency 'rspec',              '~> 3.6'
   s.add_development_dependency 'rubocop',            '~> 0.49.1'
-  s.add_development_dependency 'signet',             '~> 0.7.0'
-  s.add_development_dependency 'googleauth',         '>= 0.5.1', '< 0.7'
+  s.add_development_dependency 'signet',             '~> 0.7'
+  s.add_development_dependency 'googleauth',         '>= 0.5.1', '< 0.10'
 
   s.extensions = %w(src/ruby/ext/grpc/extconf.rb)
 

templates/grpc.gemspec.template

@@ -43,8 +43,8 @@
     s.add_development_dependency 'rake-compiler-dock', '~> 0.5.1'
     s.add_development_dependency 'rspec',              '~> 3.6'
     s.add_development_dependency 'rubocop',            '~> 0.49.1'
-    s.add_development_dependency 'signet',             '~> 0.7.0'
-    s.add_development_dependency 'googleauth',         '>= 0.5.1', '< 0.7'
+    s.add_development_dependency 'signet',             '~> 0.7'
+    s.add_development_dependency 'googleauth',         '>= 0.5.1', '< 0.10'
 
     s.extensions = %w(src/ruby/ext/grpc/extconf.rb)