ci: update to zig 0.15.2

Author: joachimschmidt557

.github/workflows/docs.yml

@@ -22,7 +22,7 @@ jobs:
     - uses: actions/checkout@v6
     - uses: mlugg/setup-zig@v2
       with:
-        version: 0.14.0
+        version: 0.15.2
     - name: Build
       run: zig build docs
     - name: Upload

.github/workflows/main.yml

@@ -16,6 +16,6 @@ jobs:
     - uses: actions/checkout@v6
     - uses: mlugg/setup-zig@v2
       with:
-        version: 0.14.0
+        version: 0.15.2
     - name: Build
       run: zig build test