build: use 3.11.0b3 in ci

Author: nedbat

.github/workflows/coverage.yml

@@ -39,7 +39,7 @@ jobs:
           - "3.8"
           - "3.9"
           - "3.10"
-          - "3.11.0-beta.1"
+          - "3.11.0-beta.3"
           - "pypy-3.7"
         exclude:
           # Windows PyPy doesn't seem to work?

.github/workflows/testsuite.yml

@@ -42,7 +42,7 @@ jobs:
           - "3.8"
           - "3.9"
           - "3.10"
-          - "3.11.0-beta.1"
+          - "3.11.0-beta.3"
           - "pypy-3.7"
         exclude:
           # Windows PyPy doesn't seem to work?

README.rst

@@ -27,7 +27,7 @@ Coverage.py runs on these versions of Python:
 
 .. PYVERSIONS
 
-* CPython 3.7 through 3.11.0b1.
+* CPython 3.7 through 3.11.0b3.
 * PyPy3 7.3.8.
 
 Documentation is on `Read the Docs`_.  Code repository and issue tracker are on