Allow lower-case base16 encoding when creating UUris from URIs

Made the rules for reading uEntity properties from URI path segments
more lenient by allowing lower-case base16 encoding as well.

This improves interoperability with uProtocol implementations that are
not strictly following the specification but generally do the right
thing.

Author: sophokles73

basics/uri.adoc

@@ -152,14 +152,14 @@ NOTE: The ABNF fragments above only contain the rules that differ from the origi
 A URI's _authority_ *MUST* be mapped to/from the UUri's `authority_name` property following the rules defined in link:https://datatracker.ietf.org/doc/html/rfc3986#section-3.2.2[RFC3986, Section 3.2.2]. In particular, the URI *MUST NOT* contain an _authority_ if `authority_name` is empty and vice versa.
 --
 
-[.specitem,oft-sid="dsn~uri-path-mapping~1",oft-needs="impl,utest"]
+[.specitem,oft-sid="dsn~uri-path-mapping~2",oft-needs="impl,utest"]
 --
 A URI's _path_ *MUST* be mapped to/from the UUri's `ue_id`, `ue_version_major` and `resource_id` properties.
 
 Each property value *MUST* be mapped to a _segment_ following the rules defined in link:https://datatracker.ietf.org/doc/html/rfc3986#section-3.3[RFC3986, Section 3.3].
 
 The `ue_id`, `ue_version_major` and `resource_id` *MUST* be mapped to the _upper-case_ link:https://www.rfc-editor.org/rfc/rfc4648#section-8[base16 encoding]
-of the corresponding property values. Leading zeros (`0`) *MAY* be omitted.
+of the corresponding property values. Leading zeros (`0`) *SHOULD* be omitted in order to reduce the length of the URI. When creating a UUri from a URI, lower-case base16 encoded values *MUST* be accepted as well in order to improve interoperability. Note that this does not conflict with the rules defined in <<Pattern Matching>>.
 --
 
 === Examples

basics/uuri_uri_serialization.feature

@@ -69,16 +69,18 @@ Feature: String representation of endpoint identfiers (UUri)
       | "/"                                   | not a URI                                             |
       | "//"                                  | not a URI                                             |
       | "//vcu.my_vin"                        | just an authority                                     |
-      | "//VCU"                               | authority with uppercase characters                   |
       | "//vcu.my_vin//1/A1FB"                | missing entity ID                                     |
       | "//vcu.my_vin/101//A1FB"              | missing version                                       |
       | "//vcu.my_vin/101/1/"                 | missing resource ID                                   |
       | "up://vcu.my_vin/101/1/A/unexpected"  | too many path segments                                |
       | "xy://vcu.my_vin/101/1/A"             | unsupported schema                                    |
       | "//vcu.my_vin/101/1/A?foo=bar"        | URI with query                                        |
       | "//vcu.my_vin/101/1/A#foo"            | URI with fragment                                     |
+      | "//VCU.my-vin/101/1/A"                | server-based authority with upper-case letters        |
       | "//vcu.my-vin:1516/101/1/A"           | server-based authority with port                      |
       | "//user:pwd@vcu.my-vin/101/1/A"       | server-based authority with user info                 |
+      | "//[2001:db87aa::8]/101/1/A"          | invalid IP literal authority                          |
+      | "//MY_VIN/101/1/A"                    | registry-based authority with uppercase characters    |
       | "//reg_based:1516/101/1/A"            | registry-based authority name with invalid characters |
       | "up://vcu.my-vin/1G1/1/A1FB"          | non-hex entity ID                                     |
       | "/123456789/1/A1FB"                   | entity ID exceeds max length                          |