fix the scrolling problem

[QiuShuiBai]

fix the scrolling problem in IOS13.4 webview

added default description of better-scroll parameter

better-scroll #978

[codecov-io]

Codecov Report

Merging #695 into dev will decrease coverage by 0.45%.
The diff coverage is 46.66%.

@@            Coverage Diff             @@
##              dev     #695      +/-   ##
==========================================
- Coverage   92.79%   92.34%   -0.46%     
==========================================
  Files         141      141              
  Lines        3083     3110      +27     
  Branches      501      510       +9     
==========================================
+ Hits         2861     2872      +11     
- Misses        116      129      +13     
- Partials      106      109       +3     

Impacted Files	Coverage Δ
src/components/picker/picker.vue	76.86% <38.88%> (-6.05%)	⬇️
src/components/scroll/scroll.vue	90.00% <58.33%> (-1.91%)	⬇️

---

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 ada7650...bfcc367. Read the comment docs.