#### What type of PR is this?
None
#### What this PR does / why we need it:
更新 issue 模板。
#### Does this PR introduce a user-facing change?
```release-note
None
```
#### What type of PR is this?
/kind improvement
#### What this PR does / why we need it:
添加[爱发电](https://afdian.net/a/halo-dev)的赞助入口，以及在 README 上添加 Sponsors 图像，此图像会在 https://github.com/halo-sigs/sponsor-images 仓库中自动更新。
#### Does this PR introduce a user-facing change?
```release-note
None
```
#### What type of PR is this?
/kind feature
/area core
#### What this PR does / why we need it:
Use Gradle plugin `maven-publish` to publish Halo modules(`platform.application`, `platform.plugin` and `api`) to Maven central repository.
```bash
# Try to publish to Maven local repository.
./gradlew publish
# Really publish to Maven central repository.
./gradlew -Prelease publish -PossrhUsername=username -PossrhPassword=password
```
Note that currently we only support manually publishing.
#### Which issue(s) this PR fixes:
Fixes https://github.com/halo-dev/halo/issues/2730
#### Does this PR introduce a user-facing change?
```release-note
None
```
#### What type of PR is this?
/kind improvement
#### What this PR does / why we need it:
移除在 https://github.com/halo-dev/halo/pull/1416 中引入的通过 GitHub Actions 来实现 ChatOps 的配置文件，目前已经使用了 Prow 代替。
#### Does this PR introduce a user-facing change?
```release-note
None
```
#### What type of PR is this?
/kind documentation
#### What this PR does / why we need it:
See https://github.com/halo-dev/halo/pull/2078 for more.
#### Does this PR introduce a user-facing change?
```release-note
None
```
#### What type of PR is this?
/kind bug
#### What this PR does / why we need it:
Add checkout-from parameter for composite action. Please see <a801af5be5/README.md>.
If we don't set the parameter for the action, it will checkout from `default branch` to build docker image. You can see <https://github.com/halo-dev/halo/runs/7316162265?check_suite_focus=true#step:2:478>.
#### Which issue(s) this PR fixes:
<!--
PR 合并时自动关闭 issue。
Automatically closes linked issue when PR is merged.
用法：`Fixes #<issue 号>`，或者 `Fixes (粘贴 issue 完整链接)`
Usage: `Fixes #<issue number>`, or `Fixes (paste link of issue)`.
-->
Fixes #
#### Special notes for your reviewer:
#### Does this PR introduce a user-facing change?
```release-note
None
```
* Refactor Dockerfile with layered jar
* Add projectVersion print task
* Refactor docker build process
* Remove aliyun maven mirror
* Correct multi platforms list
* Correct multi platforms list again
* Make docker platforms configurable
* 1196 refactor/ci (#3)
* Remove .travis.yml
* Refactor github action partially
* Fix yaml syntax error
* Add run command for every step
* Set current branch name into halo.yml temporarily
* Test validation.yml
* Add upload-release-asset step into release.yml
* Perfect release.yml
* Fix indent error
* Refactor on condition in release.yml
* Refactor on condition in validation.yml
* Fix release.yml
* Fix upload_url value set
* Fix environment set error
* Change artifact variable from output into global environment
* Fix deprecated environment set method
* Fix environment variable set error
* Change assert_content_type with application/zip
* Refactor upload release step
* Fix release id set
* Fix release id set again
* Fix syntax error
* Refactor upload process
* Refactor halo ci
* Make build step rely on check step
* Inspect docker action
* Inspect docker action again
* Refine bootBuildImage config
* Refactor bootBuildImage config and halo ci
* Fix download artifact path error
* Fix docker image name concat error
* Remove downloaded files inspect tips
* Update spring boot version and source compatibility version
* Rearrange some configs
* Upgrade swagger to 3.0.0
* Make swagger configurable
* Make swagger-ui.html path backward compatible
* Change jdk version into 11 in ci/cd scripts and Dockerfile
