chore(signing): correct Fulcio service to correct address (#1135)

<!-- markdownlint-disable MD041 -->
#### What this PR does / why we need it
correct Fulcio service to correct address, as currecnt address leads to
"no host found" when traing to sign using cosign

#### Which issue(s) this PR fixes
<!--
Usage: `Fixes #<issue number>`, or `Fixes (paste link of issue)`.
-->

---------

Co-authored-by: Hilmar Falkenberg <[email protected]>

api/tech/signing/handlers/sigstore/attr/attr.go

@@ -15,7 +15,7 @@ const (
 
 var defaultAttr = Attribute{
 	// https://github.com/tektoncd/chains/blob/main/docs/config.md#keyless-signing-with-fulcio
-	FulcioURL:    "https://v1.fulcio.sigstore.dev",
+	FulcioURL:    "https://fulcio.sigstore.dev",
 	RekorURL:     "https://rekor.sigstore.dev",
 	OIDCIssuer:   "https://oauth2.sigstore.dev/auth",
 	OIDCClientID: "sigstore",
@@ -46,7 +46,7 @@ func (a AttributeType) Description() string {
 	return `
 *sigstore config* Configuration to use for sigstore based signing.
 The following fields are used.
-- *<code>fulcioURL</code>* *string*  default is https://v1.fulcio.sigstore.dev
+- *<code>fulcioURL</code>* *string*  default is https://fulcio.sigstore.dev
 - *<code>rekorURL</code>* *string*  default is https://rekor.sigstore.dev
 - *<code>OIDCIssuer</code>* *string*  default is https://oauth2.sigstore.dev/auth
 - *<code>OIDCClientID</code>* *string*  default is sigstore

docs/reference/ocm.md

@@ -309,7 +309,7 @@ The value can be a simple type or a JSON/YAML string for complex values
 - <code>ocm.software/signing/sigstore</code> [<code>sigstore</code>]: *sigstore config* Configuration to use for sigstore based signing.
 
   The following fields are used.
-  - *<code>fulcioURL</code>* *string*  default is https://v1.fulcio.sigstore.dev
+  - *<code>fulcioURL</code>* *string*  default is https://fulcio.sigstore.dev
   - *<code>rekorURL</code>* *string*  default is https://rekor.sigstore.dev
   - *<code>OIDCIssuer</code>* *string*  default is https://oauth2.sigstore.dev/auth
   - *<code>OIDCClientID</code>* *string*  default is sigstore

docs/reference/ocm_attributes.md

@@ -201,7 +201,7 @@ OCM library:
 - <code>ocm.software/signing/sigstore</code> [<code>sigstore</code>]: *sigstore config* Configuration to use for sigstore based signing.
 
   The following fields are used.
-  - *<code>fulcioURL</code>* *string*  default is https://v1.fulcio.sigstore.dev
+  - *<code>fulcioURL</code>* *string*  default is https://fulcio.sigstore.dev
   - *<code>rekorURL</code>* *string*  default is https://rekor.sigstore.dev
   - *<code>OIDCIssuer</code>* *string*  default is https://oauth2.sigstore.dev/auth
   - *<code>OIDCClientID</code>* *string*  default is sigstore