Bump pelican from 4.11.0.post0 to 4.12.0 (#23)

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements.txt

@@ -1,5 +1,5 @@
 Jinja2==3.1.6
 Markdown==3.10.2
-Pelican[markdown]==4.11.0.post0
+Pelican[markdown]==4.12.0
 pelican-linkclass==2.1.6
 pelican-liquid-tags==1.0.4