Added newline at end of `.gitignore` files (#141270)

Added missing required newline at end of some `.gitignore` files. All other `.gitignore` files ends with a newline except the changed ones, hence the PR.

> *List which issues are fixed by this PR. You must list at least one issue. An issue is not required if the PR fixes something trivial like a typo.*

**Not listing any issues because of trivial fixes as mentioned above.**

AUTHORS

@@ -120,3 +120,4 @@ Sabin Neupane <sabin.neupane26@gmail.com>
 Mahdi Bagheri <1839491@gmail.com>
 Mok Kah Wai <taboosun1996@gmail.com>
 Lucas Saudon <lsaudon@gmail.com>
+Om Phatak <everythingoutdated@gmail.com>