Update @types/mocha to the latest version 🚀 (#226)

Author: mayurkale22

packages/opencensus-core/package-lock.json

@@ -39,7 +39,7 @@
   },
   "devDependencies": {
     "@types/continuation-local-storage": "^3.2.1",
-    "@types/mocha": "^2.2.48",
+    "@types/mocha": "^5.2.5",
     "@types/node": "^9.4.7",
     "@types/once": "^1.4.0",
     "@types/semver": "^5.5.0",

packages/opencensus-core/package.json

@@ -39,7 +39,7 @@
     "access": "public"
   },
   "devDependencies": {
-    "@types/mocha": "^2.2.48",
+    "@types/mocha": "^5.2.5",
     "@types/nock": "^9.1.3",
     "@types/node": "^9.4.7",
     "@types/semver": "^5.5.0",

packages/opencensus-exporter-instana/package-lock.json

@@ -38,7 +38,7 @@
     "access": "public"
   },
   "devDependencies": {
-    "@types/mocha": "^2.2.48",
+    "@types/mocha": "^5.2.5",
     "@types/nock": "^9.1.3",
     "@types/node": "^9.4.7",
     "@types/shimmer": "^1.0.1",

packages/opencensus-exporter-instana/package.json

@@ -45,7 +45,7 @@
     "ext": "ts"
   },
   "devDependencies": {
-    "@types/mocha": "^2.2.48",
+    "@types/mocha": "^5.2.5",
     "@types/nock": "^9.1.3",
     "@types/node": "^9.4.7",
     "@types/shimmer": "^1.0.1",