fix(comments): clarify GitObject#{since,until} (#955)

* build: schema.json and schema.d.ts updated

* update schema

---------

Co-authored-by: Octokit Bot <octokitbot@martynus.net>
Co-authored-by: Gregor Martynus <39992+gr2m@users.noreply.github.com>

Author: 3 people

schema.graphql

@@ -4865,12 +4865,14 @@ type Commit implements GitObject & Node & Subscribable & UniformResourceLocatabl
     path: String
 
     """
-    Allows specifying a beginning time or date for fetching commits.
+    Allows specifying a beginning time or date for fetching commits. Unexpected
+    results may be returned for dates not between 1970-01-01 and 2099-12-13 (inclusive).
     """
     since: GitTimestamp
 
     """
-    Allows specifying an ending time or date for fetching commits.
+    Allows specifying an ending time or date for fetching commits. Unexpected
+    results may be returned for dates not between 1970-01-01 and 2099-12-13 (inclusive).
     """
     until: GitTimestamp
   ): CommitHistoryConnection!

schema.json

@@ -12549,7 +12549,7 @@
               },
               {
                 "name": "since",
-                "description": "Allows specifying a beginning time or date for fetching commits.",
+                "description": "Allows specifying a beginning time or date for fetching commits. Unexpected results may be returned for dates not between 1970-01-01 and 2099-12-13 (inclusive).",
                 "type": {
                   "kind": "SCALAR",
                   "name": "GitTimestamp",
@@ -12559,7 +12559,7 @@
               },
               {
                 "name": "until",
-                "description": "Allows specifying an ending time or date for fetching commits.",
+                "description": "Allows specifying an ending time or date for fetching commits. Unexpected results may be returned for dates not between 1970-01-01 and 2099-12-13 (inclusive).",
                 "type": {
                   "kind": "SCALAR",
                   "name": "GitTimestamp",