Collapse updates section with two-level structure

[danielmiessler]

Description: The updates section in README is taking up too much vertical space. Need two-level collapsing structure. Acceptance Criteria: Main updates section uses details tag, each update nested in own details tag, all collapsed by default.

[danielmiessler]

Fixed: Added two-level collapsing structure to updates section. Main updates section now has a parent details tag wrapping all individual update entries.