feat: added double asterisk wildcard selector to prevent uppercasing of keys before exporting envs

[bagf]

Description

When using the wildcard to match multiple secrets to export as env variables, all keys get uppercased. There are situations where this is undesirable. To maintain backwards compatibility I've added an alterative double asterisk ** which will avoid uppercasing exported env keys.

Relates #537

Closes #536

Checklist

• Added CHANGELOG entry (only for user-facing changes)

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[bagf]

fyi i've signed the CLA but it wont change status for some reason