Fixed jinja2 environment autoescape to enable select extensions

[mstfbl]

This PR fixes an issue pointed out by Bandit w.r.t. using autoescape=False with a Jinja2 environment to avoid cross-site scripting vulnerabilities.

Bandit output:

>> Issue: [B701:jinja2_autoescape_false] Using jinja2 templates with autoescape=False is dangerous and can lead to XSS. Use autoescape=True or use the select_autoescape function to mitigate XSS vulnerabilities.
   Severity: High   Confidence: High
   Location: ./.circleci/regenerate.py:184
   More Info: https://bandit.readthedocs.io/en/latest/plugins/b701_jinja2_autoescape_false.html
183	    d = os.path.dirname(__file__)
184	    env = jinja2.Environment(
185	        loader=jinja2.FileSystemLoader(d),
186	        lstrip_blocks=True,
187	        autoescape=False,
188	    )

[codecov]

Codecov Report

Merging #1277 (450d14b) into master (93b03e4) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1277   +/-   ##
=======================================
  Coverage   78.80%   78.80%           
=======================================
  Files          67       67           
  Lines        3624     3624           
=======================================
  Hits         2856     2856           
  Misses        768      768           

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