Add support for 2023 ACS Data

[cooperjaXC]

Changes

These edits update README.rst and core.py with 2023 as default and in ACS-related tuples. This allows users to pull 2023 ACS data. This fixes Issue #150.

Notes

• Local ad-hoc tests were performed on an assortment of ACS variables. See code block below. This script succeeded in a new virtual environment with only this branch installed.
• Full transparency: I encountered some test-related issues locally when running tests/test_census.py, but they looked to be environment-related. I followed the template for updates akin to Adding 2021 to available years for ACS1Client and ACS5Client #132 that did reference this test file.
• I did not update language about the incoming congress (i.e., changing 118 → 119th) in any file.
• I’m happy to let the repository's maintainers adjust the code or tests directly if needed. The "Allow edits by maintainers" option is enabled for this PR.

# Example 1: Population by age and gender, employment status
c.acs1.us(['B01001_001E', 'B23025_005E'], year=2023)

# Example 2: Median household income, educational attainment
c.acs5.state(['B19013_001E', 'B15003_017E'], state_fips='46', year=2023)

# Example 3: Poverty status by age and gender
c.acs1.state_county(['B17001_002E', 'B17001_003E'], state_fips='06', county_fips='073', year=2023)

# Example 4: Housing units, owner-occupied housing units
c.acs5.state_place(['B01001_001E'], state_fips='12', place='45000', year=2023)

# Example 5: Means of transportation to work
c.acs5.state_legislative_district_upper(['B08301_001E', 'B08301_003E'], state_fips='06', legislative_district='10', year=2023)

# Example 6:  Population by age and gender
c.acs1.us(['C18101_001E', 'C18101_003E'], year=2023)

# Example 7: Young children by parents' employment status
c.acs5.state_congressional_district(['B23008_003E'],'15','*',year=2023)