fix: use uri-template

Signed-off-by: Matthias Pichler <m.pichler@warrify.com>

Author: matthias-pichler

examples/call-http-shorthand-endpoint.yaml

@@ -8,4 +8,4 @@ do:
     call: http
     with:
       method: get
-      endpoint: https://petstore.swagger.io/v2/pet/1
+      endpoint: https://petstore.swagger.io/v2/pet/{petId}

schema/workflow.yaml

@@ -219,7 +219,7 @@ $defs:
                 oneOf:
                   - $ref: '#/$defs/endpoint'
                   - type: string
-                    format: uri
+                    format: uri-template
               headers:
                 type: object
                 description: A name/value mapping of the headers, if any, of the HTTP request to perform.