minicap gets reinstalled every time.

Every time you connect a device, minicap will be installed.
```
[03:12:38][DEBUG] version:5
[03:12:38][DEBUG] upgrade minicap to lastest version: 5->6
```
This problem has been occurring since airtest version 1.1.5.
The following commit may be the cause.
https://github.com/AirtestProject/Airtest/pull/802/commits/e1a64bcda0a5527e5b64b130a93b28e2ecf17992

The reason is that the version of minicap was 6 until 1.1.4, but since 1.1.5, the version is 5.
https://github.com/AirtestProject/Airtest/blob/master/airtest/core/android/minicap.py#L38
The difference is caused by the fact that this constant is 6.

**To Reproduce**
Steps to reproduce the behavior:
1. Connect the device.
2. Press "connect" in the device action.
3. Check the log screen of AirtestIDE.
4. Press "disconnect" in the device action.
5. Press "connect" in the device action.
6. Check the log screen of AirtestIDE.

**Expected behavior**.
If the version of minicap is the latest, it is correct that it will not be installed.

**python version:** `python3.7.9`

**airtest version:** `1.1.8`
AirtestIDE version 1.2.7

**Smartphone (please complete the following information):**
- Device: SC-02H
- OS: Android 8.0