docs: fix broken GDAL link in cli-raster README

[olitreadwell]

Motivation

The GDAL link in packages/cli-raster/README.md points to https://github.com/gdal/gdal, which does not exist (404).

GDAL's real GitHub home is the OSGeo org: https://github.com/OSGeo/gdal.

A reader following the doc link to learn more about GDAL hits a dead end.

Modifications

• packages/cli-raster/README.md: fixed the [GDAL] link to point to https://github.com/OSGeo/gdal instead of the non-existent https://github.com/gdal/gdal.

Verification

• Confirmed the old link 404s: curl -o /dev/null -w '%{http_code}' https://github.com/gdal/gdal → 404.
• Confirmed the new link resolves: curl -o /dev/null -w '%{http_code}' https://github.com/OSGeo/gdal → 200.
• One-line docs-only change, no code affected. packages/cli-raster has no separate lint/build step for its README; the repo-wide build CI job (typecheck/lint/test via linz/action-typescript@v3) covers this PR.
• AI review (ocr delegate preview): ran in delegation mode, the reviewer's rule engine excludes .md files (unsupported_ext), so no automated findings apply to this change. Manual self-review: single URL swap, no other risk.

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Promotion note (for Oli): this is a fork-internal PR opened only against olitreadwell/basemaps.

To promote it upstream after review:

gh pr create --repo linz/basemaps --base master --head olitreadwell:docs/fix-broken-gdal-link-20260804-231558 \
  --title "docs: fix broken GDAL link in cli-raster README" \
  --body "See olitreadwell/basemaps PR for full description."

No CLA bot or DCO sign-off requirement found in this repo's CONTRIBUTING.md or .github/, so no extra prerequisite before promoting.

How to verify

git fetch https://github.com/olitreadwell/basemaps.git docs/fix-broken-gdal-link
git checkout FETCH_HEAD
--title "docs: fix broken GDAL link in cli-raster README" \
--body "See olitreadwell/basemaps PR for full description."

AI assistance

Drafted with AI assistance.

The gap was found and verified against the current code, the change was verified before opening, and this diff was reviewed line by line.

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PROMOTION NOTE (remove this section before/when opening against upstream):

gh pr create --repo linz/basemaps --base master --head olitreadwell:docs/fix-broken-gdal-link

Prerequisites: none outstanding (re-verify CLA/DCO/signing before promoting).

[olitreadwell]

Closing as duplicate: the same change was already submitted upstream in linz#3656 (MERGED). See linz#3656

[olitreadwell]

Superseded by upstream linz#3656.