[macOS] Pre-cache Ruby binaries (#2085)

* precache ruby binaries

* remove github_feed_token and minor change

* do not install ruby binaries from toolset

* remove toolcache file

images/macos/toolsets/toolset-10.15.json

@@ -190,6 +190,16 @@
                 "1.14.*",
                 "1.15.*"
             ]
+        },
+        {
+            "name": "Ruby",
+            "arch": "x64",
+            "versions": [
+                "2.4.*",
+                "2.5.*",
+                "2.6.*",
+                "2.7.*"
+            ]
         }
     ],
     "pipx": [