build(macos/windows): automatically use vcpkg

Previously `CMAKE_TOOLCHAIN_FILE` needed to be set manually, which was
kinda pointless when vcpkg is already installed and meant to be used

Signed-off-by: Seth Flynn <getchoo@tuta.io>

CMakePresets.json

@@ -41,6 +41,9 @@
 				"type": "equals",
 				"lhs": "${hostSystemName}",
 				"rhs": "Darwin"
+			},
+			"cacheVariables": {
+				"CMAKE_TOOLCHAIN_FILE": "$penv{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake"
 			}
 		},
 		{
@@ -50,6 +53,7 @@
 				"macos"
 			],
 			"cacheVariables": {
+				"CMAKE_TOOLCHAIN_FILE": "$penv{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake",
 				"CMAKE_OSX_ARCHITECTURES": "x86_64;arm64",
 				"VCPKG_TARGET_TRIPLET": "universal-osx"
 			}
@@ -76,6 +80,9 @@
 				"type": "equals",
 				"lhs": "${hostSystemName}",
 				"rhs": "Windows"
+			},
+			"cacheVariables": {
+				"CMAKE_TOOLCHAIN_FILE": "$penv{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake"
 			}
 		}
 	],