[TEP-0145] Pull in cel-go to vendor

go.mod

@@ -49,6 +49,7 @@ replace (
 require (
 	code.gitea.io/sdk/gitea v0.16.0
 	github.com/goccy/kpoward v0.1.0
+	github.com/google/cel-go v0.12.6
 	github.com/google/go-containerregistry/pkg/authn/k8schain v0.0.0-20230625233257-b8504803389b
 	github.com/sigstore/sigstore/pkg/signature/kms/aws v1.7.4
 	github.com/sigstore/sigstore/pkg/signature/kms/azure v1.7.4
@@ -86,6 +87,7 @@ require (
 	github.com/Azure/azure-sdk-for-go/sdk/security/keyvault/internal v1.0.0 // indirect
 	github.com/AzureAD/microsoft-authentication-library-for-go v1.1.1 // indirect
 	github.com/Microsoft/hcsshim v0.11.1 // indirect
+	github.com/antlr/antlr4/runtime/Go/antlr v1.4.10 // indirect
 	github.com/aws/aws-sdk-go-v2/service/kms v1.24.6 // indirect
 	github.com/aws/aws-sdk-go-v2/service/ssooidc v1.17.3 // indirect
 	github.com/cenkalti/backoff/v3 v3.2.2 // indirect
@@ -124,6 +126,7 @@ require (
 	github.com/pkg/browser v0.0.0-20210911075715-681adbf594b8 // indirect
 	github.com/ryanuber/go-glob v1.0.0 // indirect
 	github.com/skeema/knownhosts v1.2.0 // indirect
+	github.com/stoewer/go-strcase v1.2.0 // indirect
 	github.com/theupdateframework/go-tuf v0.5.2 // indirect
 	github.com/titanous/rocacheck v0.0.0-20171023193734-afe73141d399 // indirect
 	github.com/zeebo/errs v1.3.0 // indirect

pkg/apis/pipeline/v1/when_validation.go

@@ -20,6 +20,8 @@ import (
 	"fmt"
 	"strings"
 
+	// TODO(#7244): Pull the cel-go library for now, the following PR will use the library.
+	_ "github.com/google/cel-go/cel"
 	"k8s.io/apimachinery/pkg/api/equality"
 	"k8s.io/apimachinery/pkg/selection"
 	"k8s.io/apimachinery/pkg/util/sets"