chore: add pr template

[zhangyouxin]

Description

This PR aims to provide a template for PRs, thus contributors can fill out the skeleton when creating a PR.

Type of change

• docs (non-breaking change)

How Has This Been Tested?

Just try creating a PR and this template will show up for you to fill in.

An example： zhangyouxin#18

[vercel]

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[codecov]

Codecov Report

Merging #394 (6d2ca91) into develop (f244d81) will increase coverage by 0.04%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop     #394      +/-   ##
===========================================
+ Coverage    81.94%   81.98%   +0.04%     
===========================================
  Files           93       93              
  Lines        19003    19105     +102     
  Branches      1785     1794       +9     
===========================================
+ Hits         15572    15664      +92     
- Misses        3390     3400      +10     
  Partials        41       41              

Impacted Files	Coverage Δ
packages/ckb-indexer/src/services.ts	47.47% <0.00%> (-1.49%)	⬇️
packages/ckb-indexer/src/type.ts	100.00% <0.00%> (ø)
packages/ckb-indexer/src/index.ts	100.00% <0.00%> (ø)
packages/ckb-indexer/src/paramsFormatter.ts	92.30% <0.00%> (ø)
packages/ckb-indexer/src/resultFormatter.ts	95.83% <0.00%> (+0.08%)	⬆️
packages/helpers/src/index.ts	86.63% <0.00%> (+0.91%)	⬆️
packages/ckb-indexer/src/collector.ts	52.10% <0.00%> (+1.18%)	⬆️
packages/ckb-indexer/src/rpc.ts	37.93% <0.00%> (+1.56%)	⬆️

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