Upgrade dependencies

[MathiasKoch]

• [ ] heapless v0.7.0

Changes from generic_array to const generics Example:

impl<C, N, L> Dns for UbloxClient<C, N, L>
where
    C: atat::AtatClient,
    N: ArrayLength<Option<crate::sockets::SocketSetItem<L>>>,
    L: ArrayLength<u8>,
{

becomes:

impl<C, const N: usize, const L: usize> Dns for UbloxClient<C, N, L>
where
    C: atat::AtatClient
{

• [ ] embedded-nal v0.6.0

Drops the requirement of interior mutability (RefCell & Cell)

no-std-net dependency can be dropped, as those are re-exported by embedded-nal, thus not requiring us to version match the two on upgrades.

• [ ] atat v0.11.0

No big changes worth mentioning

• [ ] embedded-time v0.11.0

No changes