ci: remove macos x86 builds

The x86 GitHub runner will not be available anymore, soon.

We might be able to re-introduce this, once we can build a static
executable via Nix on darwin, too.

.github/workflows/build.yaml

@@ -105,15 +105,6 @@ jobs:
             artifact: postgrest-macos-aarch64
             deps: brew link --force libpq
 
-          - name: MacOS x86-64
-            runs-on: macos-13
-            cache: |
-              ~/.stack/pantry
-              ~/.stack/snapshots
-              ~/.stack/stack.sqlite3
-            artifact: postgrest-macos-x86-64
-            deps: brew link --force libpq
-
           - name: Windows
             runs-on: windows-2022
             cache: |

.github/workflows/release.yaml

@@ -81,9 +81,6 @@ jobs:
           tar cJvf "release-bundle/postgrest-${GITHUB_REF_NAME}-macos-aarch64.tar.xz" \
             -C artifacts/postgrest-macos-aarch64 postgrest
 
-          tar cJvf "release-bundle/postgrest-${GITHUB_REF_NAME}-macos-x86-64.tar.xz" \
-            -C artifacts/postgrest-macos-x86-64 postgrest
-
           tar cJvf "release-bundle/postgrest-${GITHUB_REF_NAME}-freebsd-x86-64.tar.xz" \
             -C artifacts/postgrest-freebsd-x86-64 postgrest