Add back nightly testing of blst dependency

[hoffmang9]

Adding back a nightly test of our upstream dependency

[coveralls-official[bot]]

Pull Request Test Coverage Report for Build 5339457047

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 94.584%

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Totals
Change from base Build 5328422783:	0.0%
Covered Lines:	1624
Relevant Lines:	1717

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💛 - Coveralls