chore(deps): update dependency open-policy-agent/conftest to v0.56.0 in dockerfile (main) (runatlantis#5035)

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

Author: renovate[bot]

Dockerfile

@@ -9,7 +9,7 @@ ARG DEFAULT_TERRAFORM_VERSION=1.9.8
 # renovate: datasource=github-releases depName=opentofu/opentofu versioning=hashicorp
 ARG DEFAULT_OPENTOFU_VERSION=1.8.3
 # renovate: datasource=github-releases depName=open-policy-agent/conftest
-ARG DEFAULT_CONFTEST_VERSION=0.55.0
+ARG DEFAULT_CONFTEST_VERSION=0.56.0
 
 # Stage 1: build artifact and download deps