Update .devcontainer/requirements.txt

.devcontainer/requirements.txt

@@ -11,7 +11,7 @@ mkdocs-multirepo-plugin==0.6.3
 mkdocs-redirects==1.2.1
 mkdocs-extra-sass-plugin==0.1.0
 mkdocs-render-swagger-plugin==0.1.1
-mkdocs-rss-plugin-1.15.0
+mkdocs-rss-plugin==1.15.0
 mkdocs-same-dir==0.1.3
 mkdocs-pdf==0.1.1
 livereload==2.6.3