do a requirements bump

notable changes:

* Flask 1.1 treats redirects to itself as relative URLs now, so a spate
  of tests were updated

requirements/requirements.txt

@@ -4,17 +4,17 @@
 #
 #    pip-compile --output-file=requirements/requirements.txt requirements/requirements.in
 #
-click==8.0.4
+click==8.1.2
     # via flask
-flask==2.0.3
+flask==2.1.1
     # via -r requirements/requirements.in
 itsdangerous==2.1.2
     # via flask
-jinja2==3.1.0
+jinja2==3.1.1
     # via flask
 markdown==3.3.6
     # via -r requirements/requirements.in
 markupsafe==2.1.1
     # via jinja2
-werkzeug==2.0.3
+werkzeug==2.1.1
     # via flask