add Printf to docs/Project.toml

Author: JoshuaLampert

docs/Project.toml

@@ -3,6 +3,7 @@ Changelog = "5217a498-cd5d-4ec6-b8c2-9b85a09b6e3e"
 Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
 OrdinaryDiffEqTsit5 = "b1df2697-797e-41e3-8120-5422d3b24e4a"
 Plots = "91a5bcdd-55d7-5caf-9e0b-520d859cae80"
+Printf = "de0858da-6303-5e67-8744-51eddeeeb8d7"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 SummationByPartsOperators = "9f78cca6-572e-554e-b819-917d2f1cf240"
 TrixiBase = "9a0f1c46-06d5-4909-a5a3-ce25d3fa3284"
@@ -12,6 +13,7 @@ Changelog = "1"
 Documenter = "1"
 OrdinaryDiffEqTsit5 = "1"
 Plots = "1.9"
+Printf = "1"
 SparseArrays = "1"
 SummationByPartsOperators = "0.5.41"
 TrixiBase = "0.1.1"