Update cosign image in validate-release job (#931)

Signed-off-by: Priya Wadhwa <priya@chainguard.dev>

Author: priyawadhwa

.github/workflows/validate-release.yml

@@ -40,7 +40,7 @@ jobs:
 
     env:
       CROSS_BUILDER_IMAGE: ghcr.io/gythialy/golang-cross:v1.17.11-0@sha256:b0c3083b0a420ff649d5a5bfd7e0a96719ab0a7b3f99a049a4950d836a72637a
-      COSIGN_IMAGE: gcr.io/projectsigstore/cosign:v1.8.0@sha256:12b4d428529654c95a7550a936cbb5c6fe93a046ea7454676cb6fb0ce566d78c
+      COSIGN_IMAGE: gcr.io/projectsigstore/cosign:v1.9.0@sha256:ef2d14e16dbb7786d8713e4898a8512e69ace4105f5b371a9c115ffcc3e85d84
 
     steps:
       - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b # v3.0.2