Update CHANGELOG.md [ci skip]

CHANGELOG.md

@@ -1,9 +1,16 @@
 # CHANGE LOG
 
+## 1.7.3
+
+* Fix erroneous encoding of `%` char in URL field of `fetch.txt` which could break already properly encoded URLs. 
+This was due to a misinterpretation of the spec which states that `%` (along with `CR` and `LF`) should _only_ be URL 
+encoded for the `filename` field and that whitespace (` ` and `\t`) should _only_ be encoded in the URL field.
+* NOTE: As a best practice, applications should always pre-encode URLs that are added to `fetch.txt` and not rely on `bdbag` to do so, since only whitespace will be encoded.
+
 ## 1.7.2
 
 * Introducing support for _bag idempotentcy_, or reproducible bags. A reproducible bag is a bag that has content-equivalence (in both payload _and_ metadata, including manifests) 
-to another bag created a different time with the same content, structure, bagging tool, and profile (if used). When this bag creation and bag archive mode is enabled, 
+to another bag created at a different time, but with the same content, structure, bagging tool, and profile (if used). When this bag creation and bag archive mode is enabled, 
 two separately created bags (or bag archive files) with content-equivalence will _hash equally_, whether the hash is calculated on the bytes of the resultant archive file or calculated on the equivalently ordered set of individual file hashes of the bag's contents. See the [API Guide](https://github.com/fair-research/bdbag/blob/master/doc/api.md) for additional information. 
 * PR: [#59](https://github.com/fair-research/bdbag/pull/59) Only require the external package `importlib_metadata` for Python < 3.8. This module is already included as `importlib.metadata` in Python versions 3.8 and above.  
 * Fix issue with HTTP fetch handler and auth header bearer-token stripping on redirects not getting restored to the cached `requests` session after redirect.