chore(deps): Bump chainguard-dev/cosign from 0.3.4 to 0.4.0

Bumps [chainguard-dev/cosign](https://github.com/chainguard-dev/terraform-provider-cosign) from 0.3.4 to 0.4.0.
- [Release notes](https://github.com/chainguard-dev/terraform-provider-cosign/releases)
- [Commits](chainguard-dev/terraform-provider-cosign@v0.3.4...v0.4.0)

---
updated-dependencies:
- dependency-name: chainguard-dev/cosign
  dependency-version: 0.4.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

main.tf

@@ -2,7 +2,7 @@ terraform {
   required_providers {
     cosign = {
       source  = "chainguard-dev/cosign"
-      version = "0.3.4"
+      version = "0.4.0"
     }
     apko = {
       source  = "chainguard-dev/apko"