Add apptainer support

Adds apptainer definition and config to automatically build the
apptainer image on release.

Part of #27

.github/workflows/deploy-apptainer.yml

@@ -0,0 +1,46 @@
+name: Create and publish an Apptainer image
+
+on:
+  release:
+    types: [published]
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  build-and-push-image:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Log in to the Container registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Apptainer
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=semver,pattern={{major}}.{{minor}}.{{patch}}
+
+      - name: Setup apptainer executable
+        uses: eWaterCycle/setup-apptainer@v2
+        with:
+          apptainer-version: 1.3.0
+
+      - name: Build an apptainer image
+        run: apptainer build --build-arg PYBIOCLIP_VERSION=${{ steps.meta.outputs.version }} bioclip.sif apptainer.def
+
+      - name: Publish apptainer image
+        run: apptainer push bioclip.sif oras://ghcr.io/johnbradley/apptainer-test:${{ steps.meta.outputs.version }}

apptainer.def

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+Bootstrap: docker
+From: condaforge/miniforge3:24.3.0-0
+
+%arguments
+    PYBIOCLIP_VERSION=
+
+%post
+   pip install "https://github.com/Imageomics/pybioclip/archive/refs/tags/{{ PYBIOCLIP_VERSION }}.tar.gz" && pip cache purge
+
+%runscript
+   exec bash