Update chat links to Zulip. (#7539)

* Update chat links to Zulip.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Fix icon path.

* Move zulip icon/path.

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

.github/ISSUE_TEMPLATE/config.yml

@@ -7,7 +7,7 @@ contact_links:
     url: https://discourse.jupyter.org/c/notebook/31
     about: If you have a question or you're having issues installing Jupyter Notebook, try posting on Discourse.
   - name: 💬 Chat with the devs
-    url: https://app.gitter.im/#/room/#jupyter_notebook:gitter.im
+    url: https://jupyter.zulipchat.com/
     about: Ask short questions about using Jupyter Notebook
   - name: 📝 Do you have a feature request that may be applied upstream? See JupyterLab.
     url: https://github.com/jupyterlab/jupyterlab

docs/source/conf.py

@@ -191,9 +191,10 @@ html_theme_options = {
             "icon": "fab fa-discourse",
         },
         {
-            "name": "Gitter",
-            "url": "https://gitter.im/jupyter/jupyter",
-            "icon": "fab fa-gitter",
+            "name": "Zulip",
+            "url": "https://jupyter.zulipchat.com/",
+            "icon": "_static/zulip-icon-square.svg",
+            "type": "local",
         },
     ],
     "logo": {