Bump cel-go to v0.17.6

vendor/github.com/google/cel-go/common/functions/BUILD.bazel

@@ -0,0 +1,17 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+package(
+    default_visibility = ["//visibility:public"],
+    licenses = ["notice"],  # Apache 2.0
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "functions.go",
+    ],
+    importpath = "github.com/google/cel-go/common/functions",
+    deps = [
+        "//common/types/ref:go_default_library",
+    ],
+)