Revert "chore: Raised iOS/tvOS target to 11.0, since this is the minimum version for Unity 2020 LTS"

It broke the build

This reverts commit 1eb874b.

Author: atteneder

.github/workflows/unity.yml

@@ -61,7 +61,7 @@ jobs:
         -DCMAKE_BUILD_TYPE=MinSizeRel
         -DCMAKE_SYSTEM_NAME=iOS
         -DCMAKE_OSX_ARCHITECTURES=armv7\;armv7s\;arm64
-        -DCMAKE_OSX_DEPLOYMENT_TARGET=11.0
+        -DCMAKE_OSX_DEPLOYMENT_TARGET=10.0
         -DDRACO_UNITY_PLUGIN=ON
         -DDRACO_GLTF_BITSTREAM=ON
         -DDRACO_BACKWARDS_COMPATIBILITY=OFF
@@ -85,7 +85,7 @@ jobs:
         cmake . -G Xcode -B build_tvos
         -DCMAKE_BUILD_TYPE=MinSizeRel
         -DCMAKE_SYSTEM_NAME=tvOS
-        -DCMAKE_OSX_DEPLOYMENT_TARGET=11.0
+        -DCMAKE_OSX_DEPLOYMENT_TARGET=10.0
         -DDRACO_UNITY_PLUGIN=ON
         -DDRACO_GLTF_BITSTREAM=ON
         -DDRACO_BACKWARDS_COMPATIBILITY=OFF