doc: Update Guardrails setup steps

[nfcodacy]

Updates the Guardrails setup steps.

[github-actions]

Overall readability score: 53.12 (🔴 -0.01)

File	Readability
codacy-guardrails-getting-started.md	57.65 (🔴 -2.5)

View detailed metrics

🟢 - Shows an increase in readability
🔴 - Shows a decrease in readability

File	Readability	FRE	GF	ARI	CLI	DCRS
codacy-guardrails-getting-started.md	57.65	50.06	11.65	12.9	10.68	7.32
	🔴 -2.5	🔴 -0.3	🔴 -0.54	🔴 -0.3	🔴 -0.18	🔴 -0.26

Averages:

	Readability	FRE	GF	ARI	CLI	DCRS
Average	53.12	42.88	10.94	12.68	12.63	7.99
	🔴 -0.01	🟢 +0	🟢 +0	🟢 +0	🟢 +0	🟢 +0

View metric targets

Metric	Range	Ideal score
Flesch Reading Ease	100 (very easy read) to 0 (extremely difficult read)	60
Gunning Fog	6 (very easy read) to 17 (extremely difficult read)	8 or less
Auto. Read. Index	6 (very easy read) to 14 (extremely difficult read)	8 or less
Coleman Liau Index	6 (very easy read) to 17 (extremely difficult read)	8 or less
Dale-Chall Readability	4.9 (very easy read) to 9.9 (extremely difficult read)	6.9 or less