feat: support gradient line for Progress

[orzyyyy]

First of all, thank you for your contribution! 😄

New feature please send pull request to feature branch, and rest to master branch.
Pull request will be merged after one of collaborators approve.
Please makes sure that these form are filled before submitting your pull request, thank you!

[中文版模板 / Chinese template]

🤔 This is a ...

• New feature
• Bug fix
• Site / document update
• Component style update
• TypeScript definition update
• Refactoring
• Code style optimization
• Branch merge
• Other (about what?)

👻 What's the background?

1. Describe the source of requirement, like related issue link.

2. Describe the problem and the scenario.

💡 Solution

1. How to fix the problem, and list final API implementation and usage sample if that is an new feature.

2. GIF or snapshot should be provided if includes UI/interactive modification.
   

   Feel free to close this if it's not in design.

📝 Changelog description

Describe changes from userside, and list all potential break changes or other risks.

1. English description

   Support gradient line color for Progress.Line

2. Chinese description (optional)

   Progress.Line 支持渐变色

☑️ Self Check before Merge

• Doc is updated/provided or not needed
• Demo is updated/provided or not needed
• TypeScript definition is updated/provided or not needed
• Changelog is provided or not needed

[netlify]

Deploy preview for ant-design processing.

Building with commit fa1900954e3eb6c8cc88b22be455e52226f3d320

https://app.netlify.com/sites/ant-design/deploys/5c90f60363248f0008c551df

[netlify]

Deploy preview for ant-design ready!

Built with commit 740f277

https://deploy-preview-15524--ant-design.netlify.com

[afc163]

这个好酷！

例子要找个好看点的配色

[codecov]

Codecov Report

Merging #15524 into feature will increase coverage by <.01%.
The diff coverage is 94.44%.

@@             Coverage Diff             @@
##           feature   #15524      +/-   ##
===========================================
+ Coverage     94.1%    94.1%   +<.01%     
===========================================
  Files          250      250              
  Lines         6637     6655      +18     
  Branches      1940     1942       +2     
===========================================
+ Hits          6246     6263      +17     
- Misses         390      391       +1     
  Partials         1        1

Impacted Files	Coverage Δ
components/progress/progress.tsx	91.66% <ø> (ø)	⬆️
components/progress/Line.tsx	96.66% <94.44%> (-3.34%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update addc7bd...740f277. Read the comment docs.

[codecov]

Codecov Report

Merging #15524 into feature will decrease coverage by 0.02%.
The diff coverage is 100%.

@@             Coverage Diff             @@
##           feature   #15524      +/-   ##
===========================================
- Coverage    94.14%   94.11%   -0.03%     
===========================================
  Files          250      250              
  Lines         6643     6647       +4     
  Branches      1931     1947      +16     
===========================================
+ Hits          6254     6256       +2     
- Misses         388      390       +2     
  Partials         1        1

Impacted Files	Coverage Δ
components/progress/progress.tsx	91.66% <ø> (ø)	⬆️
components/progress/Line.tsx	100% <100%> (ø)	⬆️
components/upload/UploadList.tsx	94.49% <0%> (-1.84%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update eacf35d...498c6d8. Read the comment docs.

[afc163]

给几个配色参考：

https://codepen.io/laurenglegg/pen/ayEpVe
https://codepen.io/nikitahl/pen/XEzbNe
https://codepen.io/Travisaurus-Rex/pen/JRPLmm

另外能不能支持 circle？

[orzyyyy]

文档里已经有红绿蓝三种颜色了，颜色太多了看起来很累，我是觉着现在这颜色挺好的...

要支持 circle 得去改 rc-progress，这又是另一个故事了...最近得准备上岸，这故事主角应该不会是我

[afc163]

This pull request introduces 1 alert when merging 2d9cc6f into addc7bd - view on LGTM.com

new alerts:

• 1 for Incomplete string escaping or encoding

---

Comment posted by LGTM.com

[dengfuping]

@zy410419243 Could you rebase the commits?

[orzyyyy]

@dengfuping Feel free to squash merge, all is related commit.