ci: replace fake julia-actions/setup-julia SHA (824fb972 → 4c0cb0fc) (#13)

`julia-actions/setup-julia@824fb972babf1837cf21c49159bf8a8130f26840` returns HTTP 422 "No commit found" —
it is a fake SHA pin, never resolved by GitHub. Every CI run on this repo
failed at `Unable to resolve action julia-actions/setup-julia@824fb972...`.

Replace with the real v3 SHA `4c0cb0fce8556fdb04a90347310e5db8b1f98fb9` (verified via
`gh api repos/julia-actions/setup-julia/commits/<sha>`).

Caught by the 2026-05-30 estate audit — one of 8 .jl repos affected
plus julia-ecosystem monorepo (9 nested workflows).

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

.github/workflows/release.yml

@@ -27,7 +27,7 @@ jobs:
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v4
 
-      - uses: julia-actions/setup-julia@824fb972babf1837cf21c49159bf8a8130f26840 # v2
+      - uses: julia-actions/setup-julia@4c0cb0fce8556fdb04a90347310e5db8b1f98fb9 # v2
         with:
           version: ${{ matrix.julia-version }}
 
@@ -56,7 +56,7 @@ jobs:
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v4
 
-      - uses: julia-actions/setup-julia@824fb972babf1837cf21c49159bf8a8130f26840 # v2
+      - uses: julia-actions/setup-julia@4c0cb0fce8556fdb04a90347310e5db8b1f98fb9 # v2
         with:
           version: '1.10'