Scheduled weekly dependency update for week 35 (#130)

* Update black from 21.7b0 to 21.8b0

* Update bleach from 4.0.0 to 4.1.0

* Update pluggy from 0.13.1 to 1.0.0

requirements.txt

@@ -2,8 +2,8 @@ asttokens==2.0.5
 appdirs==1.4.4
 atomicwrites==1.4.0
 attrs==21.2.0
-black==21.7b0
-bleach==4.0.0
+black==21.8b0
+bleach==4.1.0
 bumpversion==0.6.0
 certifi==2021.5.30
 chardet==4.0.0
@@ -19,7 +19,7 @@ Jinja2==3.0.1
 MarkupSafe==2.0.1
 more-itertools==8.8.0
 pkginfo==1.7.1
-pluggy==0.13.1
+pluggy==1.0.0
 py==1.10.0
 pyperclip==1.8.2
 Pygments==2.10.0