update dev guide for reuse config change

Author: mustafasoylu

docs/dev_guide.md

@@ -23,7 +23,7 @@ Here is a *non-exhaustive* list of the most important files and directories in t
 * `codemeta.json`: metadata for harvesting by other tools and services
 * `LICENSE`: the (main) license of the project
 * `LICENSES`: copies of all licenses that apply to files in the project
-* `.reuse/dep5`: granular license and copyright information for all files and directories
+* `REUSE.toml`: granular license and copyright information for all files and directories
 
 *Development:*