Add jupyter-cell-tags&jupyter-slideshow

[ouliuquan]

• I have read the note above about PRs contributing or fixing extensions
• I have tried reaching out to the extension maintainers about publishing this extension to Open VSX (if not, please create an issue in the extension's repo using this template).
• This extension has an OSI-approved OSS license (we don't accept proprietary extensions in this repository)

Description

These two extensions are important to install a new version of python, when I install a new version of python, downloadPlugins always shows an error:

theia-blueprint: Extension with id ms-toolsai.vscode-jupyter-slideshow not found at https://open-vsx.org/api/-/query?extensionId=ms-toolsai.vscode-jupyter-slideshow&includeAllVersions=true
theia-blueprint: Extension with id ms-toolsai.vscode-jupyter-cell-tags not found at https://open-vsx.org/api/-/query?extensionId=ms-toolsai.vscode-jupyter-cell-tags&includeAllVersions=true
theia-blueprint: Error: Errors downloading some plugins. To make these errors non fatal, re-run with --ignore-errors
theia-blueprint:     at downloadPlugins (D:\Task\theia-blueprint_1400\node_modules\@Theia\cli\lib\download-plugins.js:112:15)
theia-blueprint:     at async Object.handler (D:\Task\theia-blueprint_1400\node_modules\@Theia\cli\lib\theia.js:308:13)
error Command failed with exit code 1.

We should add all jupyter packages here, all two are MIT license.

[filiptronicek]

Thanks a lot for the contributions, changes and CI look good. Should be published by the next European morning 🌞.

[ouliuquan]

Thanks, this is the best news I heard today