Updates installation instructions in README

[jmartfrut]

Simplifies the installation instructions by removing the unnecessary repository URL, allowing the package manager to find the package automatically.

[github-actions]

Benchmark Results (Julia v1)

Time benchmarks

	main	84b5531...	main / 84b5531...
Constitutive models/Visco-elastic Ψ	0.0469 ± 0.027 ms	0.0473 ± 0.027 ms	0.99 ± 0.8
Constitutive models/Visco-elastic ∂Ψu	0.0615 ± 0.002 ms	0.0619 ± 0.0022 ms	0.994 ± 0.047
Constitutive models/Visco-elastic ∂Ψuu	0.11 ± 0.014 ms	0.111 ± 0.014 ms	0.989 ± 0.18
Simulations/StaticMechanicalDirichlet	0.135 ± 0.007 s	0.143 ± 0.01 s	0.943 ± 0.082
Simulations/StaticMechanicalNeumann	0.128 ± 0.011 s	0.136 ± 0.013 s	0.943 ± 0.12
Simulations/ViscoElastic	20.6 s	21.3 s	0.967
Tensor algebra/Cofactor	0.07 ± 0.01 μs	0.07 ± 0.01 μs	1 ± 0.2
Tensor algebra/Det(A)Inv(A')	0.13 ± 0.001 μs	0.13 ± 0.01 μs	1 ± 0.077
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	2.46 ± 0.0075 s	2.52 ± 0.044 s	0.974 ± 0.017

Memory benchmarks

	main	84b5531...	main / 84b5531...
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