Incorrect handling of '..' in url path about yarl

[panagiks]

Additional reference RFC2396:Section5

Within a relative-path reference, the complete path segments "." and
".." have special meanings: "the current hierarchy level" and "the
level above this hierarchy level", respectively.

[panagiks]

Also referring to RFC3986:Section3.3

The path segments "." and "..", also known as dot-segments, are
defined for relative reference within the path name hierarchy. They
are intended for use at the beginning of a relative-path reference
(Section 4.2) to indicate relative position within the hierarchical
tree of names. This is similar to their role within some operating
systems' file directory structures to indicate the current directory
and parent directory, respectively. However, unlike in a file
system, these dot-segments are only interpreted within the URI path
hierarchy and are removed as part of the resolution process (Section
5.2).

Note the are removed as part of the resolution process.

And the algorithm for the 'dotted path removal' is at RFC3986:Section5.2.4.