build(deps): Bump github.com/golang/protobuf from 1.4.2 to 1.4.3 (#5506)

Bumps [github.com/golang/protobuf](https://github.com/golang/protobuf) from 1.4.2 to 1.4.3.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a href="https://github.com/golang/protobuf/releases">github.com/golang/protobuf's releases</a>.</em></p>
<blockquote>
<h2>v1.4.3</h2>
<p>Notable changes:</p>
<p>(<a href="https://github-redirect.dependabot.com/golang/protobuf/issues/1221">#1221</a>) jsonpb: Fix marshaling of Duration
(<a href="https://github-redirect.dependabot.com/golang/protobuf/issues/1210">#1210</a>) proto: convert integer to rune before converting to string</p>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="4846b58453"><code>4846b58</code></a> jsonpb: Fix marshaling of Duration (<a href="https://github-redirect.dependabot.com/golang/protobuf/issues/1221">#1221</a>)</li>
<li><a href="91c84e0db1"><code>91c84e0</code></a> travis.yml: update tested versions of Go (<a href="https://github-redirect.dependabot.com/golang/protobuf/issues/1211">#1211</a>)</li>
<li><a href="3860b2764f"><code>3860b27</code></a> proto: convert integer to rune before converting to string (<a href="https://github-redirect.dependabot.com/golang/protobuf/issues/1210">#1210</a>)</li>
<li>See full diff in <a href="https://github.com/golang/protobuf/compare/v1.4.2...v1.4.3">compare view</a></li>
</ul>
</details>
<br />


[![Dependabot compatibility score](https://dependabot-badges.githubapp.com/badges/compatibility_score?dependency-name=github.com/golang/protobuf&package-manager=go_modules&previous-version=1.4.2&new-version=1.4.3)](https://docs.github.com/en/github/managing-security-vulnerabilities/configuring-github-dependabot-security-updates)

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting `@dependabot rebase`.

[//]: # (dependabot-automerge-start)
[//]: # (dependabot-automerge-end)

---

<details>
<summary>Dependabot commands and options</summary>
<br />

You can trigger Dependabot actions by commenting on this PR:
- `@dependabot rebase` will rebase this PR
- `@dependabot recreate` will recreate this PR, overwriting any edits that have been made to it
- `@dependabot merge` will merge this PR after your CI passes on it
- `@dependabot squash and merge` will squash and merge this PR after your CI passes on it
- `@dependabot cancel merge` will cancel a previously requested merge and block automerging
- `@dependabot reopen` will reopen this PR if it is closed
- `@dependabot close` will close this PR and stop Dependabot recreating it. You can achieve the same result by closing it manually
- `@dependabot ignore this major version` will close this PR and stop Dependabot creating any more for this major version (unless you reopen the PR or upgrade to it yourself)
- `@dependabot ignore this minor version` will close this PR and stop Dependabot creating any more for this minor version (unless you reopen the PR or upgrade to it yourself)
- `@dependabot ignore this dependency` will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)


</details>

go.sum

@@ -188,6 +188,8 @@ github.com/golang/protobuf v1.4.0/go.mod h1:jodUvKwWbYaEsadDk5Fwe5c77LiNKVO9IDvq
 github.com/golang/protobuf v1.4.1/go.mod h1:U8fpvMrcmy5pZrNK1lt4xCsGvpyWQ/VVv6QDs8UjoX8=
 github.com/golang/protobuf v1.4.2 h1:+Z5KGCizgyZCbGh1KZqA0fcLLkwbsjIzS4aV2v7wJX0=
 github.com/golang/protobuf v1.4.2/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
+github.com/golang/protobuf v1.4.3 h1:JjCZWpVbqXDqFVmTfYWEVTMIYrL/NPdPSCHPJ0T/raM=
+github.com/golang/protobuf v1.4.3/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
 github.com/golang/snappy v0.0.0-20180518054509-2e65f85255db/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
 github.com/golang/snappy v0.0.1 h1:Qgr9rKW7uDUkrbSmQeiDsGa8SjGyCOGtuasMWwvp2P4=
 github.com/golang/snappy v0.0.1/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=