Change expected resolver error messages in YAML tests

Author: MrMino

tests/yaml/conflict_2.yml

@@ -23,5 +23,5 @@ cases:
     - state: null
       error:
         stderr: >-
-          Cannot install six<1.12 and virtualenv 20.0.2 because these
+          Cannot install six<1.12 and virtualenv==20.0.2 because these
           package versions have conflicting dependencies.

tests/yaml/conflicting_diamond.yml

@@ -12,7 +12,7 @@ cases:
     - error:
         code: 1
         stderr: >-
-          Cannot install A and A because these package
-          versions have conflicting dependencies.
+          Cannot install A because these package versions have
+          conflicting dependencies.
         # TODO: Tweak this error message to make sense.
         # https://github.com/pypa/pip/issues/8495

tests/yaml/large.yml

@@ -287,6 +287,6 @@ cases:
       error:
         code: 1
         stderr: >-
-          Cannot install six==1.8.2, html5lib 1.0.1, six==1.8.2 and
-          html5lib 0.999999999 because these package versions have
+          Cannot install html5lib==0.999999999, html5lib==1.0.1
+          and six==1.8.2 because these package versions have
           conflicting dependencies.