Use hashlib.sha256 instead of hashlib.sha1 in gcpy/regrid.py

gcpy/regrid.py
- The CodeQL GitHub Action flagged the use of hashlib.sha1 as being
  cryptographically weak.  We have adopted the recommendation of using
  hashlib.sha256 instead.

CHANGELOG.md
- Updated accordingly

Signed-off-by: Bob Yantosca <yantosca@seas.harvard.edu>

Author: yantosca

CHANGELOG.md

@@ -40,7 +40,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
   - `make_regridder_L2S --> make_regridder_ll2sg`
 - Updated `cstools.py`, `file_regrid.py`, `append_grid_corners.py`, and `raveller_1D.py` to import and use renamed functions
 - Updated `append_grid_corners.py` to use `DEFAULT_SG_PARAMS` from `constants.py`
-- Rema,med `vert_grid` class in `gcpy/grid.py` to `VertGrid` to conform to PascalCase naming convention
+- Renamed `vert_grid` class in `gcpy/grid.py` to `VertGrid` to conform to PascalCase naming convention
+- Replaced `hashlib.sha1` with `hashlib.sha256` in routine `sg_hash` in `gcpy/regrid.py`
 
 ### Fixed
 - Fixed grid area calculation scripts of `grid_area` in `gcpy/gcpy/cstools.py`

gcpy/regrid.py

@@ -926,7 +926,7 @@ def sg_hash(
     target_lat     : float : Target latitude (degrees)
     target_lon     : float : Target longitude (degrees)
     """
-    return hashlib.sha1(
+    return hashlib.sha256(
         f'cs={cs_res},sf={stretch_factor:.5f},tx={target_lon:.5f},ty={target_lat:.5f}'.encode()
     ).hexdigest()[:7]