run subprocesses in /tmp to avoid cwd pollution

Commands like ckb-next-dev-detect write side-effect files (reports,
tarballs) into the working directory when invoked with --help. Chdir
to /tmp around create_process_env so these don't land in the project
tree.

inshellah.opam

@@ -15,6 +15,7 @@ depends: [
   "angstrom"
   "angstrom-unix"
   "camlzip"
+  "sqlite3"
   "ppx_inline_test" {with-test}
   "odoc" {with-doc}
 ]