Update Linux installation process on README to have a way to dynamically get kubeseal version number #1622

Job	Run time
Load versions.env	3s
Build (1.20.3, macos-latest, 1.8.1)	3m 0s
Build (1.20.3, windows-latest, 1.8.1)	4m 40s
Build (1.20.3, ubuntu-latest, 1.8.1)	3m 3s
Run linters (1.20.3, ubuntu-latest, 1.52.2)	4m 42s
Build Container	2m 2s
Run gosec (1.20.3, ubuntu-latest, 2.15.0)	2m 35s
Integration (controller.yaml) (1.24.15)	6m 25s
Integration (controller.yaml) (1.25.11)	8m 16s
Integration (controller.yaml) (1.26.6)	6m 13s
Integration (controller.yaml) (1.27.3)	6m 28s
Integration (Helm Chart) (1.24.15)	7m 23s
Integration (Helm Chart) (1.25.11)	5m 31s
Integration (Helm Chart) (1.26.6)	6m 35s
Integration (Helm Chart) (1.27.3)	6m 41s
	1h 13m 37s

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