release: 5.3.0

[stevenjoezhang]

Fix #4594

## Changes

- fix(load_plugins): ignore plugin whose name is started with "hexo-theme" @stevenjoezhang [#4592]
- Replace `process.mainModule` with `require.main` @stevenjoezhang [#4583]
- expose `escape_html` helper method for string manipulation to templates @awwong1 [#4581]
- list_tags: span element & custom class for label @noraj [#4578]
- fix(codeblock): closing code fence may be followed only by spaces @stevenjoezhang [#4574]
- docs(badge): replace david-dm with more reliable shields.io @curbengh [#4538]

[coveralls]

Coverage remained the same at 98.306% when pulling d22d7be on dep into a780691 on master.

[SukkaW]

It is not required to update minor or patch version if there is no packages-lock.json specified. npm will install the latest major version automatically.

[SukkaW]

Is the changelog ready?

[SukkaW]

Since #4578 introduces a new feature, I would suggest bumping a minor version instead of a patch version. Hexo 5.3.0 would be fine.

[yoshinorin]

Done :)

https://www.npmjs.com/package/hexo/v/5.3.0