Update dependency pug to v3

[mend-for-github-com]

This PR contains the following updates:

Package	Type	Update	Change
pug (source)	dependencies	major	^2.0.4 -> ^3.0.0

By merging this PR, the issue #13 will be automatically resolved and closed:

Severity	CVSS Score	CVE
High	7.4	CVE-2020-8203
High	7.2	CVE-2021-23337
Medium	6.8	CVE-2021-21353
Medium	6.8	CVE-2021-21353
Medium	5.3	CVE-2020-28500
Medium	5.3	CVE-2021-23343

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Release Notes

pugjs/pug (pug)

v3.0.0

Compare Source

Breaking Changes

• read plugins must now return Buffer if you want to support filters that use renderBuffer (#​3213)

  If you don't wish to support this advanced use case, you can continue returning string. If you did not provide a read plugin, you do not need to do anything.

• The minify option on filters now requires you to install the relevant jstransformer (#​3084)

  Currently we support:

  • jstransformer-uglify-js for JavaScript
  • jstransformer-clean-css for CSS

• Drop support for node 6 and 8 (#​3243)

New Features

• Support filters that apply to Buffers (#​3213)

  e.g.

  // options.js
  exports.filters = {
    png: {
      // instead of a function, specify an object with a "renderBuffer" property
      // whose value is a function that takes a Buffer instead of a string
      renderBuffer: function(buffer, options) {
        var data = Buffer.from(buffer).toString('base64');
        return '<img src="data:image/png;base64, ' + data + '"/>';
      }
    }
  };

  You can then use the filter like:

  // foo.pug
  include:png my-small-image.png

• Add support for replacing code gen via a plugin with generateCode (#​3230)

• Support each ... of ... loops (#​3179)

  each value of iterable
    li= value

  This requires an environment that supports the for (const val of iterable) syntax in JS. You can iterate over Maps, Sets etc. as well as arrays. There is also some destructuring of map keys:

  - const map = new Map([['a', 'x'], ['b', 'y']]);
  each [key, value] of map
    li
      strong= key
      = value

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