Fix shellcheck issues in workflows

[samford]

shellcheck is reporting an SC2086 ("Double quote to prevent globbing and word splitting") issue in the update-database.yml workflow. This adds quotes around the related area to resolve the issue.

There are other shellcheck issues in handler.sh but I figured that was best left to someone who's familiar with the file and/or better at shell scripting:

In /opt/homebrew/Library/Taps/homebrew/homebrew-command-not-found/handler.sh line 12:
if ! which brew >/dev/null; then return; fi
     ^---^ SC2230 (info): 'which' is non-standard. Use builtin 'command -v' instead.


In /opt/homebrew/Library/Taps/homebrew/homebrew-command-not-found/handler.sh line 22:
  if test -z "${CONTINUOUS_INTEGRATION}" && test -n "${MC_SID}" -o ! -t 1
              ^-----------------------^ SC2154 (warning): CONTINUOUS_INTEGRATION is referenced but not assigned.
                                                     ^-------^ SC2154 (warning): MC_SID is referenced but not assigned.


In /opt/homebrew/Library/Taps/homebrew/homebrew-command-not-found/handler.sh line 27:
    [[ -n "${ZSH_VERSION}" ]] && [[ "${ZSH_VERSION}" > "5.2" ]] &&
                                                       ^---^ SC2072 (error): Decimals are not supported. Either use integers only, or use bc or awk to compare.


In /opt/homebrew/Library/Taps/homebrew/homebrew-command-not-found/handler.sh line 34:
    local txt="$(brew which-formula --explain "${cmd}" 2>/dev/null)"
          ^-^ SC2155 (warning): Declare and assign separately to avoid masking return values.


In /opt/homebrew/Library/Taps/homebrew/homebrew-command-not-found/handler.sh line 43:
    [[ -n "${ZSH_VERSION}" ]] && [[ "${ZSH_VERSION}" > "5.2" ]] &&
                                                       ^---^ SC2072 (error): Decimals are not supported. Either use integers only, or use bc or awk to compare.

For more information:
  https://www.shellcheck.net/wiki/SC2072 -- Decimals are not supported. Eithe...
  https://www.shellcheck.net/wiki/SC2154 -- CONTINUOUS_INTEGRATION is referen...
  https://www.shellcheck.net/wiki/SC2155 -- Declare and assign separately to ...

Feel free to push handler.sh fixes to this branch if you know how to address the issues and we want to handle this all in one PR.

Related to Homebrew/brew#17482

[MikeMcQuaid]

thanks again @samford!