Updated upb to allow nonzero offset minutes in JSON timestamps. (#8258)

* Updated upb to allow nonzero offset minutes in JSON timestamps.

This is to pick up https://github.com/protocolbuffers/upb/pull/367

* Reverted error message change.

* Fixed quote chars.
diff --git a/ruby/ext/google/protobuf_c/ruby-upb.c b/ruby/ext/google/protobuf_c/ruby-upb.c
index 9c048da..a7aeda2 100755
--- a/ruby/ext/google/protobuf_c/ruby-upb.c
+++ b/ruby/ext/google/protobuf_c/ruby-upb.c
@@ -7793,7 +7793,8 @@
 
   {
     /* [+-]08:00 or Z */
-    int ofs = 0;
+    int ofs_hour = 0;
+    int ofs_min = 0;
     bool neg = false;
 
     if (ptr == end) goto malformed;
@@ -7804,9 +7805,10 @@
         /* fallthrough */
       case '+':
         if ((end - ptr) != 5) goto malformed;
-        ofs = jsondec_tsdigits(d, &ptr, 2, ":00");
-        ofs *= 60 * 60;
-        seconds.int64_val += (neg ? ofs : -ofs);
+        ofs_hour = jsondec_tsdigits(d, &ptr, 2, ":");
+        ofs_min = jsondec_tsdigits(d, &ptr, 2, NULL);
+        ofs_min = ((ofs_hour * 60) + ofs_min) * 60;
+        seconds.int64_val += (neg ? ofs_min : -ofs_min);
         break;
       case 'Z':
         if (ptr != end) goto malformed;