Fixing loading precompiled Ruby extension on 2.x.10+
diff --git a/src/ruby/lib/grpc/grpc.rb b/src/ruby/lib/grpc/grpc.rb
index b60a828..720e821 100644
--- a/src/ruby/lib/grpc/grpc.rb
+++ b/src/ruby/lib/grpc/grpc.rb
@@ -28,7 +28,8 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 begin
-  require_relative "#{RUBY_VERSION.sub(/\.\d$/, '')}/grpc_c"
+  RUBY_VERSION =~ /(\d+\.\d+)/
+  require "#{$1}/grpc_c"
 rescue LoadError
   require_relative 'grpc_c'
 end