Use GitHub releases to download Go versions. (#58)

package.json

@@ -23,10 +23,10 @@
   "author": "GitHub",
   "license": "MIT",
   "dependencies": {
-    "@actions/core": "^1.2.2",
+    "@actions/core": "^1.2.3",
     "@actions/http-client": "^1.0.6",
     "@actions/io": "^1.0.2",
-    "@actions/tool-cache": "^1.3.3",
+    "@actions/tool-cache": "^1.5.5",
     "semver": "^6.1.1"
   },
   "devDependencies": {
@@ -39,6 +39,6 @@
     "nock": "^10.0.6",
     "prettier": "^1.17.1",
     "ts-jest": "^24.0.2",
-    "typescript": "^3.5.1"
+    "typescript": "^3.8.3"
   }
 }