PR: Fix broken links to SciPy site and others in workshops

[CAM-Gerlach]

Pull Request

Pull Request Checklist

• [x] Read and followed this repo's Contributing Guidelines
• [x] Based your PR on the latest version of the correct branch (master or 4.x)
• [x] Checked your writing carefully for correct English spelling, grammar, etc
• [x] Described your changes and the motivation for them below
• [x] Noted what issue(s) this pull request resolves, creating one if needed

Description of Changes

There's a broken (and rather non-canonical) link to SciPy in the financial analysis workshop which was causing linkcheck to fail. This fixes that. Followup of PR #302 and implict blocker to #301

[CAM-Gerlach]

Since this is just fixing a few broken links, is failing the build on master and thus blocking PR #301 , and per the checks this now fixes it, I'm going to go ahead and merge this.