Added template for CHANGELOG

[miguelmaso]

Given we've started to package HyperFEM, it's good to have a file to track changes.

FYI @jmartfrut

[github-actions]

Benchmark Results (Julia v1)

Time benchmarks

	main	2ed93e1...	main / 2ed93e1...
Constitutive models/Visco-elastic Ψ	0.0525 ± 0.037 ms	0.0526 ± 0.037 ms	0.998 ± 0.99
Constitutive models/Visco-elastic ∂Ψu	0.0652 ± 0.0029 ms	0.0655 ± 0.0025 ms	0.995 ± 0.058
Constitutive models/Visco-elastic ∂Ψuu	0.115 ± 0.013 ms	0.116 ± 0.013 ms	0.993 ± 0.16
Simulations/StaticMechanicalDirichlet	0.136 ± 0.009 s	0.137 ± 0.0097 s	0.994 ± 0.096
Simulations/StaticMechanicalNeumann	0.13 ± 0.015 s	0.13 ± 0.017 s	0.999 ± 0.18
Simulations/ViscoElastic	21.9 s	21.7 s	1.01
Tensor algebra/Cofactor	0.09 ± 0.01 μs	0.07 ± 0 μs	1.29 ± 0.14
Tensor algebra/Det(A)Inv(A')	0.15 ± 0.01 μs	0.13 ± 0.01 μs	1.15 ± 0.12
Tensor algebra/δδ_λ_2d	30 ± 0 ns	30 ± 0 ns	1 ± 0
Tensor algebra/δδ_μ_2d	30 ± 0 ns	30 ± 0 ns	1 ± 0
time_to_load	2.54 ± 0.033 s	2.81 ± 0.021 s	0.902 ± 0.014

Memory benchmarks

	main	2ed93e1...	main / 2ed93e1...
Constitutive models/Visco-elastic Ψ	1.24 k allocs: 0.0777 MB	1.24 k allocs: 0.0777 MB	1
Constitutive models/Visco-elastic ∂Ψu	1.36 k allocs: 0.0898 MB	1.36 k allocs: 0.0898 MB	1
Constitutive models/Visco-elastic ∂Ψuu	2.32 k allocs: 0.155 MB	2.32 k allocs: 0.155 MB	1
Simulations/StaticMechanicalDirichlet	1.51 M allocs: 0.109 GB	1.51 M allocs: 0.109 GB	1
Simulations/StaticMechanicalNeumann	1.48 M allocs: 0.0933 GB	1.48 M allocs: 0.0933 GB	1
Simulations/ViscoElastic	0.343 G allocs: 22 GB	0.343 G allocs: 22 GB	1
Tensor algebra/Cofactor	1 allocs: 0.0781 kB	1 allocs: 0.0781 kB	1
Tensor algebra/Det(A)Inv(A')	4 allocs: 0.25 kB	4 allocs: 0.25 kB	1
Tensor algebra/δδ_λ_2d	0 allocs: 0 B	0 allocs: 0 B
Tensor algebra/δδ_μ_2d	0 allocs: 0 B	0 allocs: 0 B
time_to_load	0.149 k allocs: 11.1 kB	0.149 k allocs: 11.1 kB	1