Use "set -x" when the debug parameter is set

[alexeyr-ci]

Describe Request:

Even with debug: true, I only get this output for the Slack - Sending Notification step:

[]
Posting Status
Checking For JQ + CURL: Debian
14 packages can be upgraded. Run 'apt list --upgradable' to see them.
The following additional packages will be installed:
  libjq1 libonig5
The following NEW packages will be installed:
  jq libjq1 libonig5
0 upgraded, 3 newly installed, 0 to remove and 14 not upgraded.
Need to get 313 kB of archives.
After this operation, 1062 kB of additional disk space will be used.
debconf: unable to initialize frontend: Dialog
debconf: (Dialog frontend will not work on a dumb terminal, an emacs shell buffer, or without a controlling terminal.)
debconf: falling back to frontend: Readline
Selecting previously unselected package libonig5:amd64.
(Reading database ... 85656 files and directories currently installed.)
Preparing to unpack .../libonig5_6.9.4-1_amd64.deb ...
Unpacking libonig5:amd64 (6.9.4-1) ...
Selecting previously unselected package libjq1:amd64.
Preparing to unpack .../libjq1_1.6-1ubuntu0.20.04.1_amd64.deb ...
Unpacking libjq1:amd64 (1.6-1ubuntu0.20.04.1) ...
Selecting previously unselected package jq.
Preparing to unpack .../jq_1.6-1ubuntu0.20.04.1_amd64.deb ...
Unpacking jq (1.6-1ubuntu0.20.04.1) ...
Setting up libonig5:amd64 (6.9.4-1) ...
Setting up libjq1:amd64 (1.6-1ubuntu0.20.04.1) ...
Setting up jq (1.6-1ubuntu0.20.04.1) ...
Processing triggers for man-db (2.9.1-1) ...
Processing triggers for libc-bin (2.31-0ubuntu9.9) ...
parse error: Invalid string: control characters from U+0000 through U+001F must be escaped at line 9, column 159
parse error: Invalid string: control characters from U+0000 through U+001F must be escaped at line 9, column 159

Exited with code exit status 4
CircleCI received exit code 4

(not counting the script itself). After rerunning with SSH, /tmp/slack-orb/logs/post-to-slack.json contains just []. It would be much easier to find the problem if I knew which step of the script failed and what JSON was involved, which set -x would give me.

Our orb version is 4.6.1, and a comment says previous attempts to upgrade to 4.9.3 gave some cryptic errors, so maybe this is better in the current versions already?

Examples:

Supporting Documentation Links:

[alexeyr-ci]

Checked that the same is true in 4.11.0 at least.