`PATH` Not Adjusted for All Cases

[geigerj0]

PR #50 introduced a change that adjusts PATH to include the devbox binary only in the case of cache misses. However, PATH should always be updated to include ~/.local/bin, regardless of whether there’s a cache hit or miss.

GitHub.com-hosted runners already include ~/.local/bin in PATH by default, which likely explains why this issue hasn't surfaced yet.

However, for self hosted runners that do not include ~/.local/bin in PATH, the devbox-install-action fails with the following error in case of cache hits as of version v0.12.0:

/__w/_temp/b8c918eb-b7a4-460b-9115-94f59456d885.sh: line 1: devbox: command not found