remove dependency matrix from asv.ci.conf.json (astropy#16296)

* remove dependency matrix from benchmarking config

* also package results into artifact

.github/workflows/ci_benchmark.yml

@@ -101,4 +101,6 @@ jobs:
         if: always()
         with:
           name: asv-benchmark-results
-          path: benchmarks.log
+          path: |
+            results/
+            benchmarks.log

asv.ci.conf.json

@@ -3,19 +3,12 @@
    "project": "astropy",
    "project_url": "http://www.astropy.org/",
    "repo": ".",
-   "build_command": [
-     "python -m build --wheel -o {build_cache_dir} {build_dir}"
+   "install_command": [
+     "pip install . matplotlib scipy"
    ],
    "branches": ["main"],
    "show_commit_url": "http://github.com/astropy/astropy/commit/",
    "pythons": ["3.11"],
-   "matrix": {
-     "Cython": [],
-     "build": [],
-     "packaging": [],
-     "scipy": [],
-     "matplotlib": []
-   },
    "environment_type": "virtualenv",
    "benchmark_dir": "astropy-benchmarks/benchmarks"
  }