after the previous commit, i did
```
python3.8 -m venv .venv38
source .venv38/bin/activate
pip install .
excalibur initdb
excalibur webserver
```
and got the app running, but then when I uploaded a pdf I got this error:
```
ERROR:root:PdfFileReader is deprecated and was removed in PyPDF2 3.0.0. Use PdfReader instead.
Traceback (most recent call last):
File "/Users/valeriomariani/Desktop/test_excalibur/excalibur/.venv38/lib/python3.8/site-packages/excalibur/tasks.py", line 22, in split
extract_pages, total_pages = get_pages(file.filepath, file.pages)
File "/Users/valeriomariani/Desktop/test_excalibur/excalibur/.venv38/lib/python3.8/site-packages/excalibur/utils/task.py", line 29, in get_pages
infile = PdfFileReader(inputstream, strict=False)
File "/Users/valeriomariani/Desktop/test_excalibur/excalibur/.venv38/lib/python3.8/site-packages/PyPDF2/_reader.py", line 1974, in __init__
deprecation_with_replacement("PdfFileReader", "PdfReader", "3.0.0")
File "/Users/valeriomariani/Desktop/test_excalibur/excalibur/.venv38/lib/python3.8/site-packages/PyPDF2/_utils.py", line 369, in deprecation_with_replacement
deprecation(DEPR_MSG_HAPPENED.format(old_name, removed_in, new_name))
File "/Users/valeriomariani/Desktop/test_excalibur/excalibur/.venv38/lib/python3.8/site-packages/PyPDF2/_utils.py", line 351, in deprecation
raise DeprecationError(msg)
PyPDF2.errors.DeprecationError: PdfFileReader is deprecated and was removed in PyPDF2 3.0.0. Use PdfReader instead.
```
so i fixed PyPDF2==2.0 and the app manages to read pdfs and detect tables, but when i try to "view and download data" i get this:
```
ERROR:root:to_excel() got an unexpected keyword argument 'encoding'
Traceback (most recent call last):
File "/Users/valeriomariani/Desktop/test_excalibur/excalibur/.venv38/lib/python3.8/site-packages/excalibur/tasks.py", line 126, in extract
tables.export(f_datapath, f=f, compress=True)
File "/Users/valeriomariani/Desktop/test_excalibur/excalibur/.venv38/lib/python3.8/site-packages/camelot/core.py", line 736, in export
table.df.to_excel(writer, sheet_name=sheet_name, encoding="utf-8")
TypeError: to_excel() got an unexpected keyword argument 'encoding'
```