ci: Add dependabot configuration for monthly updates #273

Job	Run time
Code quality (ty and ruff)	42s
Build documentation	59s
Link correctness	7s
Tests (py3.12, ubuntu-latest, float32, full)	1m 28s
Tests (py3.10, ubuntu-latest, float32, full)	1m 21s
Tests (py3.14, ubuntu-latest, float32, full)	1m 34s
Tests (py3.13, ubuntu-latest, float32, full)	1m 23s
Tests (py3.10.0, ubuntu-latest, float32, full, lower_bounds)	1m 8s
Tests (py3.14, windows-latest, float32, full)	1m 24s
Tests (py3.14, ubuntu-latest, float32, none)	7m 47s
Tests (py3.14, ubuntu-latest, float64, full)	1m 16s
Tests (py3.11, ubuntu-latest, float32, full)	1m 20s
Tests (py3.14, macOS-latest, float32, full)	1m 1s
	21m 30s

Provide feedback