CompatHelper: bump compat for GNSSSignals to 3, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the GNSSSignals package from 2 to 2, 3.
This keeps the compat entries for earlier versions.

Note: I have not tested your package with this new compat entry.
It is your responsibility to make sure that your package tests pass before you merge this pull request.

[github-actions]

Benchmark Results (Julia v1)

Time benchmarks

	master	a0cf2bc...	master / a0cf2bc...
calc_pvt/GPSL1/4sats/cold	0.0337 ± 0.0035 ms	0.0337 ± 0.0033 ms	0.998 ± 0.14
calc_pvt/GPSL1/4sats/warm	28.6 ± 3.6 μs	28.6 ± 3.7 μs	0.999 ± 0.18
calc_pvt/GPSL1/9sats/cold	0.0426 ± 0.00087 ms	0.0431 ± 0.00084 ms	0.989 ± 0.028
calc_pvt/GPSL1/9sats/warm	19.5 ± 0.56 μs	19.6 ± 0.57 μs	0.994 ± 0.041
calc_pvt/GalileoE1B/4sats/cold	0.0323 ± 0.005 ms	0.0322 ± 0.0055 ms	1 ± 0.23
calc_pvt/GalileoE1B/4sats/warm	12.5 ± 0.53 μs	12.2 ± 0.49 μs	1.02 ± 0.06
calc_pvt/GalileoE1B/5sats/cold	0.0333 ± 0.0042 ms	0.0333 ± 0.0043 ms	1 ± 0.18
calc_pvt/GalileoE1B/5sats/warm	13.8 ± 0.48 μs	13.6 ± 0.5 μs	1.01 ± 0.052
time_to_load	2.44 ± 0.013 s	2.43 ± 0.014 s	1 ± 0.0078

Memory benchmarks

	master	a0cf2bc...	master / a0cf2bc...
calc_pvt/GPSL1/4sats/cold	0.312 k allocs: 16.9 kB	0.312 k allocs: 16.9 kB	1
calc_pvt/GPSL1/4sats/warm	0.257 k allocs: 14 kB	0.257 k allocs: 14 kB	1
calc_pvt/GPSL1/9sats/cold	0.295 k allocs: 18.3 kB	0.295 k allocs: 18.3 kB	1
calc_pvt/GPSL1/9sats/warm	0.141 k allocs: 9.02 kB	0.141 k allocs: 9.02 kB	1
calc_pvt/GalileoE1B/4sats/cold	0.301 k allocs: 16.3 kB	0.301 k allocs: 16.3 kB	1
calc_pvt/GalileoE1B/4sats/warm	0.136 k allocs: 7.09 kB	0.136 k allocs: 7.09 kB	1
calc_pvt/GalileoE1B/5sats/cold	0.291 k allocs: 16 kB	0.291 k allocs: 16 kB	1
calc_pvt/GalileoE1B/5sats/warm	0.137 k allocs: 7.34 kB	0.137 k allocs: 7.34 kB	1
time_to_load	0.149 k allocs: 11.2 kB	0.149 k allocs: 11.2 kB	1

[zsoerenm]

GNSSSignals is already at v3