fix(ci): modify syntax of insider installation

requirements.txt

@@ -3,7 +3,7 @@ mkdocs-git-authors-plugin<1
 mkdocs-git-committers-plugin-2<3
 mkdocs-git-revision-date-localized-plugin<2
 mkdocs-glightbox<1
-mkdocs-material[imaging] @ git+https://github.com/squidfunk/mkdocs-material-insiders.git@master
+git+https://github.com/squidfunk/mkdocs-material-insiders.git@master#egg=mkdocs-material[imaging]
 mkdocs-minify-plugin<1
 mkdocs-rss-plugin<2
 mkdocs-table-reader-plugin<3