Update dependency org.pitest:pitest to v1.21.0 (#1403)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

build.gradle

@@ -172,7 +172,7 @@ def versions = [
         lombok                          : '1.18.42',
         mapStruct                       : '1.3.0.Final',
         pact_version                    : '4.1.34',
-        piTest                          : '1.20.5',
+        piTest                          : '1.21.0',
         probateCommonsVersion           : '2.2.12',
         restAssured                     : '5.5.6',
         serenity                        : '4.2.34',