Create dependabot.yml

[ranocha]

This allows to get updates for GitHub actions automatically - it is basically an equivalent of CompatHelper. I have used this for my own packages, the Trixi.jl framework, and the SciML organization. After merging this, you could also enable other Dependabot actions in 'Settings -> Code security and analysis -> Dependabot alerts' and '... -> Dependabot security updates'.

See SciML/MuladdMacro.jl#37

[github-actions]

Benchmark Results

	master	f278d95...	t[master]/t[f278d95...]
overhead/acrule/a+2	1.08 ± 0.26 μs	1.09 ± 0.26 μs	0.991
overhead/acrule/a+2+b	1.08 ± 0.27 μs	1.07 ± 0.26 μs	1.01
overhead/acrule/a+b	0.354 ± 0.0077 μs	0.352 ± 0.0077 μs	1.01
overhead/acrule/noop:Int	26.2 ± 0.4 ns	26.8 ± 0.9 ns	0.978
overhead/acrule/noop:Sym	0.0465 ± 0.0078 μs	0.0489 ± 0.0076 μs	0.951
overhead/rule/noop:Int	0.0442 ± 0.0014 μs	0.0437 ± 0.0015 μs	1.01
overhead/rule/noop:Sym	0.0596 ± 0.0027 μs	0.0589 ± 0.0024 μs	1.01
overhead/rule/noop:Term	0.0596 ± 0.0028 μs	0.0592 ± 0.0025 μs	1.01
overhead/ruleset/noop:Int	0.186 ± 0.0062 μs	0.165 ± 0.0028 μs	1.12
overhead/ruleset/noop:Sym	0.195 ± 0.0073 μs	0.222 ± 0.0078 μs	0.877
overhead/ruleset/noop:Term	4.31 ± 0.29 μs	4.51 ± 0.31 μs	0.956
overhead/simplify/noop:Int	0.226 ± 0.0052 μs	0.24 ± 0.0098 μs	0.941
overhead/simplify/noop:Sym	0.237 ± 0.005 μs	0.257 ± 0.0065 μs	0.923
overhead/simplify/noop:Term	0.0451 ± 0.0037 ms	0.0455 ± 0.0038 ms	0.991
overhead/simplify/randterm (+, *):serial	0.127 ± 0.0021 s	0.129 ± 0.002 s	0.985
overhead/simplify/randterm (+, *):thread	0.0792 ± 0.018 s	0.0738 ± 0.018 s	1.07
overhead/simplify/randterm (/, *):serial	0.28 ± 0.0091 ms	0.282 ± 0.011 ms	0.993
overhead/simplify/randterm (/, *):thread	0.325 ± 0.011 ms	0.326 ± 0.011 ms	0.995
overhead/substitute/a	0.0724 ± 0.002 ms	0.0753 ± 0.0021 ms	0.961
overhead/substitute/a,b	0.0631 ± 0.0018 ms	0.0659 ± 0.0021 ms	0.958
overhead/substitute/a,b,c	22 ± 0.8 μs	23.3 ± 0.9 μs	0.944
polyform/easy_iszero	0.0389 ± 0.0032 ms	0.0397 ± 0.0034 ms	0.98
polyform/isone	3.1 ± 0.1 ns	3.1 ± 0.1 ns	1
polyform/iszero	1.62 ± 0.036 ms	1.66 ± 0.037 ms	0.979
polyform/simplify_fractions	2.29 ± 0.039 ms	2.33 ± 0.041 ms	0.985
time_to_load	5.51 ± 0.027 s	5.51 ± 0.012 s	1

Benchmark Plots

A plot of the benchmark results have been uploaded as an artifact to the workflow run for this PR.
Go to "Actions"->"Benchmark a pull request"->[the most recent run]->"Artifacts" (at the bottom).