More informative instruction to generate citation files (#264)

Show people how to easily use our `CITATION.cff` to generate the
citation file they need (e.g., `Bibtex`).

Author: DonggeLiu

Diff for: CITATION.cff

@@ -1,5 +1,5 @@
 cff-version: 1.2.0
-title: 'https://github.com/google/oss-fuzz-gen'
+title: 'OSS-Fuzz-Gen: Automated Fuzz Target Generation'
 message: >-
   If you use this software, please cite it using the
   metadata from this file.

Diff for: README.md

@@ -80,4 +80,4 @@ These bugs could only have been discovered with newly generated targets. They we
 OSS-Fuzz build process for the entire project.
 
 ## Citing This Work
-Please refer to the `CITATION.cff` file in this repository for citation details.
+Please click on the _'Cite this repository'_ button located on the right-hand side of this GitHub page for citation details.