Merge PR #264, Update README with renamed namespace

Checksum namespace changed from `ICSharpCode.SharpZipLib.Checksums.*` to `ICSharpCode.SharpZipLib.Checksum.*`.

Co-authored-by: ronaldbarendse <ronaldbarendse@users.noreply.github.com>

Author: ronaldbarendse

README.md

@@ -24,7 +24,7 @@ Namespace layout
 | Module | Namespace |
 |:----------------:|:-----------------------------|
 |BZip2 implementation|ICSharpCode.SharpZipLib.BZip2.\*|
-|Checksum implementation|ICSharpCode.SharpZipLib.Checksums.\*|
+|Checksum implementation|ICSharpCode.SharpZipLib.Checksum.\*|
 |Core utilities / interfaces|ICSharpCode.SharpZipLib.Core.\*|
 |Encryption implementation|ICSharpCode.SharpZipLib.Encryption.\*|
 |GZip implementation|ICSharpCode.SharpZipLib.GZip.\*|