remove gitpod and Dockerfile ignore on .gitattributes

Author: KevsterAmp

.gitattributes

@@ -65,14 +65,12 @@ pandas/_version.py export-subst
 asv_bench export-ignore
 ci export-ignore
 doc export-ignore
-gitpod export-ignore
 MANIFEST.in export-ignore
 scripts/** export-ignore
 typings export-ignore
 web export-ignore
 CITATION.cff export-ignore
 codecov.yml export-ignore
-Dockerfile export-ignore
 environment.yml export-ignore
 setup.py export-ignore