pin requirements.txt

This PR pins the requirements for this app. Initially, this was done to fix an issue with merging two DataFrames (which broke because of an API change in Pandas). Adding pinned requirements should also protect against future breaks due to library changes.

The requirements lock was generated using the [pip-tools](https://github.com/jazzband/pip-tools) `pip-compile` command against a `requirements.in` file with the following content:

```
datasets
plotly
matplotlib
pandas<=1.5.3
```

To update this in the future, you can install pip-tools and run `pip-compile --resolver=backtracking`

requirements.txt

@@ -1,3 +1,120 @@
-datasets
-plotly
-matplotlib
+#
+# This file is autogenerated by pip-compile with Python 3.8
+# by the following command:
+#
+#    pip-compile --resolver=backtracking
+#
+aiohttp==3.8.4
+    # via
+    #   datasets
+    #   fsspec
+aiosignal==1.3.1
+    # via aiohttp
+async-timeout==4.0.2
+    # via aiohttp
+attrs==23.1.0
+    # via aiohttp
+certifi==2023.5.7
+    # via requests
+charset-normalizer==3.1.0
+    # via
+    #   aiohttp
+    #   requests
+contourpy==1.1.0
+    # via matplotlib
+cycler==0.11.0
+    # via matplotlib
+datasets==2.13.1
+    # via -r requirements.in
+dill==0.3.6
+    # via
+    #   datasets
+    #   multiprocess
+filelock==3.12.2
+    # via huggingface-hub
+fonttools==4.40.0
+    # via matplotlib
+frozenlist==1.3.3
+    # via
+    #   aiohttp
+    #   aiosignal
+fsspec[http]==2023.6.0
+    # via
+    #   datasets
+    #   huggingface-hub
+huggingface-hub==0.15.1
+    # via datasets
+idna==3.4
+    # via
+    #   requests
+    #   yarl
+importlib-resources==5.12.0
+    # via matplotlib
+kiwisolver==1.4.4
+    # via matplotlib
+matplotlib==3.7.1
+    # via -r requirements.in
+multidict==6.0.4
+    # via
+    #   aiohttp
+    #   yarl
+multiprocess==0.70.14
+    # via datasets
+numpy==1.24.4
+    # via
+    #   contourpy
+    #   datasets
+    #   matplotlib
+    #   pandas
+    #   pyarrow
+packaging==23.1
+    # via
+    #   datasets
+    #   huggingface-hub
+    #   matplotlib
+    #   plotly
+pandas==1.5.3
+    # via
+    #   -r requirements.in
+    #   datasets
+pillow==10.0.0
+    # via matplotlib
+plotly==5.15.0
+    # via -r requirements.in
+pyarrow==12.0.1
+    # via datasets
+pyparsing==3.1.0
+    # via matplotlib
+python-dateutil==2.8.2
+    # via
+    #   matplotlib
+    #   pandas
+pytz==2023.3
+    # via pandas
+pyyaml==6.0
+    # via
+    #   datasets
+    #   huggingface-hub
+requests==2.31.0
+    # via
+    #   datasets
+    #   fsspec
+    #   huggingface-hub
+six==1.16.0
+    # via python-dateutil
+tenacity==8.2.2
+    # via plotly
+tqdm==4.65.0
+    # via
+    #   datasets
+    #   huggingface-hub
+typing-extensions==4.7.1
+    # via huggingface-hub
+urllib3==2.0.3
+    # via requests
+xxhash==3.2.0
+    # via datasets
+yarl==1.9.2
+    # via aiohttp
+zipp==3.15.0
+    # via importlib-resources