Remove dependency on third-party matches crate

[notriddle]

Now that the MSRV is 1.45, this macro can be assumed to exist, since it was introduced in 1.42.

[codecov-commenter]

Codecov Report

Merging #755 (fd62d12) into master (8e3e91d) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #755      +/-   ##
==========================================
+ Coverage   85.31%   85.33%   +0.02%     
==========================================
  Files          22       22              
  Lines        3894     3894              
==========================================
+ Hits         3322     3323       +1     
+ Misses        572      571       -1     

Impacted Files	Coverage Δ
data-url/src/lib.rs	82.60% <ø> (ø)
form_urlencoded/src/lib.rs	68.65% <ø> (ø)
idna/src/lib.rs	66.66% <ø> (ø)
url/src/lib.rs	75.76% <ø> (ø)
url/src/host.rs	96.95% <100.00%> (ø)
data-url/tests/wpt.rs	85.71% <0.00%> (+1.29%)	⬆️

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