Update dependency ts-loader to v6 (#72)

Author: renovate-bot

packages/opencensus-web-all/package-lock.json

@@ -61,7 +61,7 @@
     "karma-spec-reporter": "0.0.32",
     "karma-webpack": "^4.0.0-rc.5",
     "rimraf": "^2.6.2",
-    "ts-loader": "^5.1.0",
+    "ts-loader": "^6.0.0",
     "tslib": "^1.9.3",
     "typescript": "^3.3.3333",
     "webpack": "^4.18.0",

packages/opencensus-web-all/package.json

@@ -55,7 +55,7 @@
     "karma-spec-reporter": "0.0.32",
     "karma-webpack": "^4.0.0-rc.5",
     "rimraf": "^2.6.2",
-    "ts-loader": "^5.1.0",
+    "ts-loader": "^6.0.0",
     "typescript": "^3.1.6",
     "webpack": "^4.18.0",
     "webpack-cli": "^3.1.0"

packages/opencensus-web-core/package-lock.json

@@ -55,7 +55,7 @@
     "karma-spec-reporter": "0.0.32",
     "karma-webpack": "^4.0.0-rc.5",
     "rimraf": "^2.6.2",
-    "ts-loader": "^5.1.0",
+    "ts-loader": "^6.0.0",
     "typescript": "^3.1.6",
     "webpack": "^4.18.0",
     "webpack-cli": "^3.1.0"