build: pin pylint-test==1.0.3

This avoids mysterious errors:
reverbc/pylint-pytest#20

Author: Ned Batchelder

requirements/constraints.txt

@@ -7,3 +7,7 @@
 # link to other information that will help people in the future to remove the
 # pin when possible.  Writing an issue against the offending project and
 # linking to it here is good.
+
+# Not sure why I'm getting cannot-enumerate-pytest-fixtures failures:
+# https://github.com/reverbc/pylint-pytest/issues/20
+pylint-pytest==1.0.3

requirements/dev.txt

@@ -210,8 +210,10 @@ pylint==2.8.3
     # via
     #   -r requirements/quality.txt
     #   pylint-pytest
-pylint-pytest==1.1.2
-    # via -r requirements/quality.txt
+pylint-pytest==1.0.3
+    # via
+    #   -c requirements/constraints.txt
+    #   -r requirements/quality.txt
 pyparsing==2.4.7
     # via
     #   -r requirements/quality.txt

requirements/quality.txt

@@ -168,8 +168,10 @@ pygments==2.9.0
     #   sphinx
 pylint==2.8.3
     # via pylint-pytest
-pylint-pytest==1.1.2
-    # via -r requirements/quality.in
+pylint-pytest==1.0.3
+    # via
+    #   -c requirements/constraints.txt
+    #   -r requirements/quality.in
 pyparsing==2.4.7
     # via
     #   -r requirements/doc.txt