v6.42.0

OrdinaryDiffEq v6.42.0

Diff since v6.41.0

Closed issues:

• Precompilation error (DelayDiffEq v5.40.6) (#1856)
• Precompilation problem (OrdinaryDiffEq v6.41.0) (#1857)
• Issues precompiling (#1861)

Merged pull requests:

• Add MSRK54 method (#1854) (@ErikQQY)
• MSRK54 -> Stepanov5 and correct doc string (#1855) (@YingboMa)
• Unbox interpolant (#1858) (@chriselrod)
• Add MSRK6 method (#1859) (@ErikQQY)
• Minor clean up (#1862) (@YingboMa)
• fix typo (#1863) (@vpuri3)
• abstractdiffeqop -> abstractscimlop (#1864) (@vpuri3)