fix: Use quotes around extreme int64 values (#1206)

JSON numbers are only really expected to be precise as far as IEEE-754 64-bit binary floating point numbers; that means precision is lost for very large integers.
The proto3 JSON specification says that 64-bit integers should be encoded as strings, although numeric values can be parsed.

Fixes #1205

server/services/compliance_suite.json

@@ -105,11 +105,11 @@
             "fSfixed32": 2147483647,
             "fUint32": 4294967295,
             "fFixed32": 4294967295,
-            "fInt64": 9223372036854775807,
-            "fSint64": 9223372036854775807,
-            "fSfixed64": 9223372036854775807,
-            "fUint64": 18446744073709551615,
-            "fFixed64": 18446744073709551615,
+            "fInt64": "9223372036854775807",
+            "fSint64": "9223372036854775807",
+            "fSfixed64": "9223372036854775807",
+            "fUint64": "18446744073709551615",
+            "fFixed64": "18446744073709551615",
             "fDouble": 1.797693134862315708145274237317043567981e+308,
             "fFloat": 3.40282346638528859811704183484516925440e+38,
             "fBool": false,