fix(deps): update dependency @google-cloud/pubsub to ^0.28.0

fix(deps): update dependency @google-cloud/pubsub to ^0.28.0

This PR contains the following updates:

| Package | Type | Update | Change | References |
|---|---|---|---|---|
| @​google-cloud/pubsub | dependencies | minor | [`^0.27.0` -> `^0.28.0`](https://diff.intrinsic.com/@google-cloud/pubsub/0.27.1/0.28.1) | [source](https://togithub.com/googleapis/nodejs-pubsub) |
| @​google-cloud/pubsub | devDependencies | minor | [`^0.27.0` -> `^0.28.0`](https://diff.intrinsic.com/@google-cloud/pubsub/0.27.1/0.28.1) | [source](https://togithub.com/googleapis/nodejs-pubsub) |

---

### Release Notes

<details>
<summary>googleapis/nodejs-pubsub</summary>

### [`v0.28.1`](https://togithub.com/googleapis/nodejs-pubsub/blob/master/CHANGELOG.md#v0281)

[Compare Source](https://togithub.com/googleapis/nodejs-pubsub/compare/v0.28.0...v0.28.1)

03-11-2019 15:36 PDT

##### Bug Fixes

-   fix(typescript): correctly import long ([#&#8203;541](https://togithub.com/googleapis/nodejs-pubsub/pull/541))

##### Internal / Testing Changes

-   testing: set skipLibCheck to false for ts install test ([#&#8203;543](https://togithub.com/googleapis/nodejs-pubsub/pull/543))
-   refactor: fix/simplify proto gen scripts ([#&#8203;542](https://togithub.com/googleapis/nodejs-pubsub/pull/542))

### [`v0.28.0`](https://togithub.com/googleapis/nodejs-pubsub/blob/master/CHANGELOG.md#v0280)

[Compare Source](https://togithub.com/googleapis/nodejs-pubsub/compare/v0.27.1...v0.28.0)

03-11-2019 09:11 PDT

##### New Features

-   feat(topic): create setMetadata method ([#&#8203;537](https://togithub.com/googleapis/nodejs-pubsub/pull/537))

##### Dependencies

-   fix(deps): update dependency [@&#8203;google-cloud/paginator](https://togithub.com/google-cloud/paginator) to ^0.2.0

##### Internal / Testing Changes

-   build: Add docuploader credentials to node publish jobs ([#&#8203;533](https://togithub.com/googleapis/nodejs-pubsub/pull/533))
-   test: add missing packages and install test ([#&#8203;536](https://togithub.com/googleapis/nodejs-pubsub/pull/536))
-   refactor(typescript): noImplicitAny for Subscription test file ([#&#8203;534](https://togithub.com/googleapis/nodejs-pubsub/pull/534))

</details>

---

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#627 automerged by dpebot

package.json

@@ -72,7 +72,7 @@
   },
   "devDependencies": {
     "@google-cloud/nodejs-repo-tools": "^3.0.0",
-    "@google-cloud/pubsub": "^0.27.0",
+    "@google-cloud/pubsub": "^0.28.0",
     "@types/arrify": "^1.0.4",
     "@types/async": "^2.0.49",
     "@types/compressible": "^2.0.0",

samples/package.json

@@ -16,7 +16,7 @@
     "test": "mocha system-test/*.js --timeout 600000"
   },
   "dependencies": {
-    "@google-cloud/pubsub": "^0.27.0",
+    "@google-cloud/pubsub": "^0.28.0",
     "@google-cloud/storage": "^2.4.2",
     "uuid": "^3.3.2",
     "yargs": "^13.0.0"