Fix 'repository' field in kmath's package.json

[jeremywiebe]

Summary:

While working on some automation, I noticed that this package still points to its old repository (before we moved everything into this monorepo)

Issue: "none"

Test plan:

Review the change. Hpoe it's correct!

[github-actions]

Size Change: 0 B

Total Size: 1.48 MB

ℹ️ View Unchanged

Filename	Size
packages/kas/dist/es/index.js	39 kB
packages/keypad-context/dist/es/index.js	760 B
packages/kmath/dist/es/index.js	86.8 kB
packages/math-input/dist/es/index.js	77.6 kB
packages/math-input/dist/es/strings.js	1.79 kB
packages/perseus-core/dist/es/index.js	43.1 kB
packages/perseus-editor/dist/es/index.js	688 kB
packages/perseus-linter/dist/es/index.js	22.2 kB
packages/perseus-score/dist/es/index.js	113 kB
packages/perseus/dist/es/index.js	381 kB
packages/perseus/dist/es/strings.js	5.82 kB
packages/pure-markdown/dist/es/index.js	3.66 kB
packages/simple-markdown/dist/es/index.js	12.5 kB

_{compressed-size-action}

[github-actions]

npm Snapshot: Published

Good news!! We've packaged up the latest commit from this PR (a74e50e) and published it to npm. You
can install it using the tag PR2162.

Example:

yarn add @khanacademy/perseus@PR2162

If you are working in Khan Academy's webapp, you can run:

./dev/tools/bump_perseus_version.sh -t PR2162

[catandthemachines]

Looks right to me!