Fix deps for *.deb on Ubuntu 19.10

```
lsb_release -a:
Distributor ID: Ubuntu
Description: Ubuntu 19.10
Release: 19.10
Codename: eoan

Python3 Version: 3.7.5
```
When installing Dragonfire on Ubuntu 19.10, installation fails due to dependency issues. The following error is reported:

```
The following packages have unmet dependencies:
dragonfire : Depends: python3 (< 3.7) but 3.7.5-1 is to be installed
Depends: portaudio19-dev but it is not going to be installed
```

`portaudio19-dev` is in the repos, so why it says it is not going to be installed, I don't know:
```
$ apt search portaudio19-dev
Sorting... Done
Full Text Search... Done
portaudio19-dev/eoan 19.6.0-1 amd64
Portable audio I/O - development files

```
MANUALLY installing `portaudio19-dev` does resolve the problem with that package, but the python problem persists.

The command I used for installation was:
```
sudo apt install ./dragonfire_1.0.4_amd64.deb
```
This works the same as the `dpkg -i` command listed on the `README.md`, but also handles dependencies, just for disclosure.