bump default version to v2.4.0 release (#168)

Signed-off-by: Bob Callaway <bcallaway@google.com>

action.yml

@@ -10,7 +10,7 @@ inputs:
   cosign-release:
     description: 'cosign release version to be installed'
     required: false
-    default: 'v2.2.4'
+    default: 'v2.4.0'
   install-dir:
     description: 'Where to install the cosign binary'
     required: false
@@ -65,13 +65,13 @@ runs:
           esac
         }
 
-        bootstrap_version='v2.2.4'
-        bootstrap_linux_amd64_sha='97a6a1e15668a75fc4ff7a4dc4cb2f098f929cbea2f12faa9de31db6b42b17d7'
-        bootstrap_linux_arm_sha='ad0338117c8c97a555e48ee194f400aad56803aaa1f39f537a3ede9261bc9aa7'
-        bootstrap_linux_arm64_sha='658087351e1d4f9c396b5f59ee5437461c06128f4ce80ba899ccaa1c0b6a8a62'
-        bootstrap_darwin_amd64_sha='0e5a77a86115e4c00ba4243db01abceacb13cc06981c45e53ee71f2e1db8ce25'
-        bootstrap_darwin_arm64_sha='fcd310e64ecddc1eaa13fe814ac1c9fc02f6f9eacd9a58480ab8160eb8ca381e'
-        bootstrap_windows_amd64_sha='9e9b71bd3fa2a6abfa903b5f784d9ca0fbc29c563d2b084c1a82c593c2bab001'
+        bootstrap_version='v2.4.0'
+        bootstrap_linux_amd64_sha='cd7636b3586a3bdac2d9c8f3b421ed119edcb20499107887fd929211110e8418'
+        bootstrap_linux_arm_sha='b662538e82e872d8865dd7fde8b5f24950eec1b9fe0c0c6d734d31220c0e52f2'
+        bootstrap_linux_arm64_sha='e9db44c01057395230d0454144c676e7231bff08249620b0170ea19ff201de94'
+        bootstrap_darwin_amd64_sha='4d568e3bf56d254948a749d1442eedb6dc624af0a1acea082e260ba66b9feb08'
+        bootstrap_darwin_arm64_sha='779f57759a9863dacea1256fa7f116319790dfcd4f9f8b33abc30251b1f4a883'
+        bootstrap_windows_amd64_sha='88f1addbae6bdd83ec2c067470c1f56b6d0d3ba35f49ad34603f2502cb2933f3'
         cosign_executable_name=cosign
 
         trap "popd >/dev/null" EXIT