Fix link format for CHANGELOG.md

Links with 'ref format' (single pairs of square brackets and a
reference at the end) aren't a universal standard, so replace them
with the more standard inline format like `[text](url)`.

CHANGELOG.md

@@ -1,10 +1,9 @@
 # Changelog
 
-## [0.3.0] - 2025-01-22
+## [0.3.0](https://github.com/anowacki/SeisRequests.jl/compare/v0.2.3...v0.3.0) - 2025-01-22
 
 ### Breaking changes
 - SeisRequests now saves sensor burial depth in the `station.meta.burial_depth`
   entry, rather than in `station.dep`.  This is for future compatibility with
   changes to Seis.jl.
 
-[0.3.0]: https://github.com/anowacki/SeisRequests.jl/compare/v0.2.3...v0.3.0