Fix rfc3986.is_valid_uri deprecation warnings

The rfc3986.is_valid_uri has been deprecated in 1.1.0.
It generates the following warnings.

DeprecationWarning: Please use rfc3986.validators.Validator instead.
This method will be eventually removed.

So this patch replaces rfc3986.is_valid_uri with
rfc3986.validators.Validator.

Even after applying this patch, the warnings are still output
because it is caused by oslo.config.
The fix for oslo.config will be done in another patch.

Change-Id: I70aebad6c6bd384dbd11ef732226356922bf1913
Closes-Bug: #1809755

lower-constraints.txt

@@ -140,7 +140,7 @@ requests-mock==1.2.0
 requests==2.14.2
 requestsexceptions==1.4.0
 retrying==1.3.3
-rfc3986==0.3.1
+rfc3986==1.1.0
 Routes==2.3.1
 simplejson==3.13.2
 six==1.10.0

nova/api/validation/validators.py

@@ -87,8 +87,17 @@ def _validate_uuid_format(instance):
 
 @jsonschema.FormatChecker.cls_checks('uri')
 def _validate_uri(instance):
-    return rfc3986.is_valid_uri(instance, require_scheme=True,
-                                require_authority=True)
+    uri = rfc3986.uri_reference(instance)
+    validator = rfc3986.validators.Validator().require_presence_of(
+        'scheme', 'host',
+    ).check_validity_of(
+        'scheme', 'userinfo', 'host', 'path', 'query', 'fragment',
+    )
+    try:
+        validator.validate(uri)
+    except rfc3986.exceptions.RFC3986Exception:
+        return False
+    return True
 
 
 @jsonschema.FormatChecker.cls_checks('name_with_leading_trailing_spaces',

requirements.txt

@@ -51,7 +51,7 @@ oslo.policy>=1.35.0 # Apache-2.0
 oslo.privsep>=1.23.0 # Apache-2.0
 oslo.i18n>=3.15.3 # Apache-2.0
 oslo.service>=1.33.0 # Apache-2.0
-rfc3986>=0.3.1 # Apache-2.0
+rfc3986>=1.1.0 # Apache-2.0
 oslo.middleware>=3.31.0 # Apache-2.0
 psutil>=3.2.2 # BSD
 oslo.versionedobjects>=1.33.3 # Apache-2.0