chore: remove 1.8 checks

Author: avik-pal

src/dual.jl

@@ -298,8 +298,6 @@ Base.copy(d::Dual) = d
 Base.eps(d::Dual) = eps(value(d))
 Base.eps(::Type{D}) where {D<:Dual} = eps(valtype(D))
 
-# The `base` keyword was added in Julia 1.8:
-# https://github.com/JuliaLang/julia/pull/42428
 Base.precision(d::Dual; base::Integer=2) = precision(value(d); base=base)
 function Base.precision(::Type{D}; base::Integer=2) where {D<:Dual}
     precision(valtype(D); base=base)

test/DualTest.jl

@@ -118,7 +118,6 @@ ForwardDiff.:≺(::Type{OuterTestTag}, ::Type{TestTag}) = false
         @test precision(typeof(FDNUM)) === precision(V)
         @test precision(NESTED_FDNUM) === precision(PRIMAL)
         @test precision(typeof(NESTED_FDNUM)) === precision(V)
-        
         @test precision(FDNUM; base=10) === precision(PRIMAL; base=10)
         @test precision(typeof(FDNUM); base=10) === precision(V; base=10)
         @test precision(NESTED_FDNUM; base=10) === precision(PRIMAL; base=10)