Optimized Docker build to fix OOM errors

Dockerfile

@@ -17,7 +17,7 @@ ENV MAX_JOBS=1
 RUN git clone --depth 1 https://github.com/NVlabs/nvdiffrast.git /tmp/nvdiffrast \
     && cd /tmp/nvdiffrast \
     && python3 setup.py install \
-    && python3 - <<'PY'\nimport sysconfig\nfrom pathlib import Path\nsite = Path(sysconfig.get_paths()[\"purelib\"])\ndist = site / \"nvdiffrast-0.0.0.dist-info\"\ndist.mkdir(exist_ok=True)\n(dist / \"METADATA\").write_text(\"Metadata-Version: 2.1\\nName: nvdiffrast\\nVersion: 0.0.0\\n\")\n(dist / \"WHEEL\").write_text(\"Wheel-Version: 1.0\\nGenerator: manual\\nRoot-Is-Purelib: false\\nTag: py3-none-any\\n\")\n(dist / \"top_level.txt\").write_text(\"nvdiffrast\\n\")\n(dist / \"RECORD\").write_text(\"\")\nPY \
+    && python3 -c \"import sysconfig; from pathlib import Path; site = Path(sysconfig.get_paths()['purelib']); dist = site / 'nvdiffrast-0.0.0.dist-info'; dist.mkdir(exist_ok=True); (dist / 'METADATA').write_text('Metadata-Version: 2.1\\\\nName: nvdiffrast\\\\nVersion: 0.0.0\\\\n'); (dist / 'WHEEL').write_text('Wheel-Version: 1.0\\\\nGenerator: manual\\\\nRoot-Is-Purelib: false\\\\nTag: py3-none-any\\\\n'); (dist / 'top_level.txt').write_text('nvdiffrast\\\\n'); (dist / 'RECORD').write_text('')\" \
     && python3 -c "import nvdiffrast.torch" \
     && rm -rf /tmp/nvdiffrast