Bump pygments from 2.7.1 to 2.7.2 in /requirements (#15833)

Bumps [pygments](https://github.com/pygments/pygments) from 2.7.1 to 2.7.2.
- [Release notes](https://github.com/pygments/pygments/releases)
- [Changelog](https://github.com/pygments/pygments/blob/master/CHANGES)
- [Commits](pygments/pygments@2.7.1...2.7.2)

Signed-off-by: dependabot[bot] <[email protected]>

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

Author: dependabot[bot]

requirements/docs.txt

@@ -5,9 +5,9 @@ Jinja2==2.11.2 \
     --hash=sha256:89aab215427ef59c34ad58735269eb58b1a5808103067f7bb9d5836c651b3bb0 \
     --hash=sha256:f0a4641d3cf955324a89c04f3d94663aa4d638abe8f733ecd3582848e1c37035
 # Pygments is required by Sphinx
-Pygments==2.7.1 \
-    --hash=sha256:307543fe65c0947b126e83dd5a61bd8acbd84abec11f43caebaf5534cbc17998 \
-    --hash=sha256:926c3f319eda178d1bd90851e4317e6d8cdb5e292a3386aac9bd75eca29cf9c7
+Pygments==2.7.2 \
+    --hash=sha256:88a0bbcd659fcb9573703957c6b9cff9fab7295e6e76db54c9d00ae42df32773 \
+    --hash=sha256:381985fcc551eb9d37c52088a32914e00517e57f4a21609f48141ba08e193fa0
 # Sphinx is required by sphinxcontrib-httpdomain
 Sphinx==3.2.1 \
     --hash=sha256:ce6fd7ff5b215af39e2fcd44d4a321f6694b4530b6f2b2109b64d120773faea0 \