[2048] Fix reward overflow

[sotetsuk]

This state transition returns -92 as reward due to overflow.
This PR changes int8 to int32 and update version to v1.

[codecov]

Codecov Report

Merging #1034 (5ffc667) into main (4c899ab) will decrease coverage by 0.01%.
The diff coverage is 75.00%.

❗ Current head 5ffc667 differs from pull request most recent head 5e941de. Consider uploading reports for the commit 5e941de to get more accurate results

@@            Coverage Diff             @@
##             main    #1034      +/-   ##
==========================================
- Coverage   89.56%   89.55%   -0.01%     
==========================================
  Files          54       54              
  Lines        6006     6005       -1     
==========================================
- Hits         5379     5378       -1     
  Misses        627      627              

Files Changed	Coverage Δ
pgx/play2048.py	95.60% <75.00%> (-0.05%)	⬇️