How to fix kernel issue after upgrading from 18.10 to 19.04?

The analysis of source code says that grubcfg_proxy is related to grub-customizer package.

At first I can't find the reason why it is located in /etc/grub.d/bin/grubcfg_proxy on your system. This was actual for old versions, but not for current versions.
At second it is strange that it tries to load libcrypto.so.1.0.0, while regular Ubuntu 19.04 has libcrypto.so.1.1 (shipped with libssl1.1 package).
The third moment is that grubcfg_proxy file on disco is renamed to grubcfg-proxy and located in /usr/lib/grub-customizer/grubcfg-proxy.

So I'll suggest to move your binary file out the way with

sudo mv /etc/grub.d/bin/grubcfg_proxy ~/

then to be completely sure I'll recommend to purge current version of GRUB Customizer with

sudo apt-get purge grub-customizer

then update GRUB configuration:

sudo update-grub

and finally install upgrades:

sudo apt-get upgrade

If you need to use grub-customizer install its package from official repository with

sudo apt-get install grub-customizer

and use it as before.

I experienced the same problem with grubcfg_proxy not finding libcrypto.so.1.0.0 in an expected location, during the cleanup phase of updating from ubuntu 18.04 to 19.04.

I posted my fix on the related shared library missing question here:

Ubuntu 18.04: libcrypto.so.1.0.0: cannot open shared object file: No such file or directory