use `group_by()` instead

In ubuntu 22.04 with a fresh R 4.3.2 installation, I got this warning after invoking slide():

Lagging cycle by 1 time units.

Warning message:
`group_by_()` was deprecated in dplyr 0.7.0.
ℹ Please use `group_by()` instead.
ℹ See vignette('programming') for more help
ℹ The deprecated feature was likely used in the DataCombine package.
Please report the issue at .
This warning is displayed once every 8 hours.
Call `lifecycle::last_lifecycle_warnings()` to see where this warning was generated.
>
> lifecycle::last_lifecycle_warnings()
[[1]]

Warning:
`group_by_()` was deprecated in dplyr 0.7.0.
ℹ Please use `group_by()` instead.
ℹ See vignette('programming') for more help
ℹ The deprecated feature was likely used in the DataCombine package.
Please report the issue at .
---
Backtrace:
▆
1. └─DataCombine::slide(...)
2. └─dplyr::group_by_(data, .dots = GroupVar)
3. └─dplyr:::lazy_deprec("group_by")

>