[BUG] Bashtop crashes after a short time

**Describe the bug**

I've only seen this on a Ryzen Threadripper system with 24 cores. On a couple of smaller systems I haven't run into it. After running for a short time (it varies, but usually it's < 1m), bashtop crashes back to the prompt, with no error message.

Here's an error.log. There seem to be at least two different errors causing crashes.

[error.log](https://github.com/aristocratos/bashtop/files/4910610/error.log)

**To Reproduce**

I did nothing special - I launched bashtop from a fish shell running in a Terminator window on Ubuntu 20.04.

**Expected behavior**

Well, bashtop should provide hours of beautifully-formatted information.

**Screenshots**

N/A

**Info (please complete the following information):**
- Bashtop version: tip of master on 13Jul, SHA is 236e0f7dbb.
- (Linux) Linux distribution and version: Ubuntu 20.04
- (Linux) Data collection type (/proc or psutil): psutil
- (OSX/FreeBSD) Os release version:
- Terminal used: Terminator
- Font used: Hack NF Regular
- Bash version, "bash --version" (version 4.4 or above is required): GNU bash, version 5.0.16(1)-release (x86_64-pc-linux-gnu)
- Locales: output of "locale -v"
LANG=en_US.UTF-8
LANGUAGE=
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_PAPER="en_US.UTF-8"
LC_NAME="en_US.UTF-8"
LC_ADDRESS="en_US.UTF-8"
LC_TELEPHONE="en_US.UTF-8"
LC_MEASUREMENT="en_US.UTF-8"
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=

**Additional context**

contents of `$HOME/.config/bashtop/error.log`
[error.log](https://github.com/aristocratos/bashtop/files/4910610/error.log)

(enable error-logging in "$HOME/.config/bashtop/bashtop.cfg" if missing)