Update the canvas npm package to fix Travis CI builds (issue 10790)

[Snuffleupagus]

Fixes #10790

[Snuffleupagus]

This seems to have worked, however there's now a new failure related to rounding:

Failures:
1) parser Lexer getNumber should parse PostScript numbers
  Message:
    Expected 0.000009999999999999999 to equal 0.00001.
  Stack:
    Error: Expected 0.000009999999999999999 to equal 0.00001.
        at <Jasmine>
        at UserContext.<anonymous> (/home/travis/build/mozilla/pdf.js/build/lib/test/unit/parser_spec.js:96:37)
        at <Jasmine>

Apparently Chromium is no longer able to correctly evaluate Math.pow(10, -5), or other negative exponents, without introducing rounding errors :-(
In my opinion, adding hacks to the core code to work-around this isn't really acceptable given the possible performance overhead. If we care about trying to "fix" this, allowing fuzzy matching in the should parse PostScript numbers unit-tests seems like a better option to me.

[brendandahl]

Strange that it changed, https://stackoverflow.com/questions/55958535/strange-result-for-math-pow-in-javascript-across-different-browsers

[timvandermeij]

/botio unittest

[pdfjsbot]

From: Bot.io (Windows)

---

Received

Command cmd_unittest from @timvandermeij received. Current queue size: 0

Live output at: http://54.215.176.217:8877/f8762ba6fc3b25e/output.txt

[pdfjsbot]

From: Bot.io (Linux m4)

---

Received

Command cmd_unittest from @timvandermeij received. Current queue size: 0

Live output at: http://54.67.70.0:8877/c0f65c1c068cbf0/output.txt

[pdfjsbot]

From: Bot.io (Linux m4)

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Success

Full output at http://54.67.70.0:8877/c0f65c1c068cbf0/output.txt

Total script time: 2.69 mins

• Unit Tests: Passed

[pdfjsbot]

From: Bot.io (Windows)

---

Success

Full output at http://54.215.176.217:8877/f8762ba6fc3b25e/output.txt

Total script time: 5.62 mins

• Unit Tests: Passed

[timvandermeij]

Looks good!