FIX #1678: update isReadyLock state to fix deadlock on second render

[IlyaSV]

calling "render()" twice fixes some render issues (see #1678 ).
This update fixes deadlock on calling second "render()".

[codecov-commenter]

Codecov Report

Merging #1679 (661388a) into master (873eccb) will increase coverage by 0.04%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1679      +/-   ##
==========================================
+ Coverage   78.60%   78.64%   +0.04%     
==========================================
  Files          74       74              
  Lines        3010     3011       +1     
  Branches      624      624              
==========================================
+ Hits         2366     2368       +2     
  Misses        590      590              
+ Partials       54       53       -1     

Flag	Coverage Δ
base	27.03% <100.00%> (+25.87%)	⬆️
browser	0.00% <0.00%> (ø)
node	78.61% <100.00%> (+<0.01%)	⬆️
offscreen	0.00% <0.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/Screen.ts	72.02% <100.00%> (+0.66%)	⬆️

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[dangreen]

Hi. Thank you for your contribution. Could you please also add some tests for it?

[IlyaSV]

Hi. Thank you for your contribution. Could you please also add some tests for it?

Hi, @dangreen . I'm new in this project, so could you please show me a file there such async test should be placed?

[dangreen]

@IlyaSV Please create file test/canvg.spec.ts

import { Canvg } from '../src'

describe('Canvg', () => {
  describe('render', () => {
    it('should render twice without deadlock', () => {
      // ...
    });
  })
})

[dangreen]

@IlyaSV Thank you!