[AltServer] Refactors Mail plug-in installation to fix notarization errors

AltServer must now download the Mail plug-in at runtime, because notarization will fail if AltServer contains an unsigned binary (and as of Catalina, Mail plug-ins only work if they’re unsigned)

Podfile.lock

@@ -14,7 +14,7 @@ PODS:
   - Nuke (7.6.3)
   - Roxas (0.1)
   - Sparkle (1.21.3)
-  - STPrivilegedTask (1.0.1)
+  - STPrivilegedTask (1.0.7)
 
 DEPENDENCIES:
   - AltSign (from `Dependencies/AltSign`)
@@ -22,20 +22,26 @@ DEPENDENCIES:
   - Nuke (~> 7.0)
   - Roxas (from `Dependencies/Roxas`)
   - Sparkle
-  - STPrivilegedTask
+  - STPrivilegedTask (from `https://github.com/rileytestut/STPrivilegedTask.git`)
 
 SPEC REPOS:
   trunk:
     - KeychainAccess
     - Nuke
     - Sparkle
-    - STPrivilegedTask
 
 EXTERNAL SOURCES:
   AltSign:
     :path: Dependencies/AltSign
   Roxas:
     :path: Dependencies/Roxas
+  STPrivilegedTask:
+    :git: https://github.com/rileytestut/STPrivilegedTask.git
+
+CHECKOUT OPTIONS:
+  STPrivilegedTask:
+    :commit: c8dd3e41b23666d4010c86b052a921a8e5a320d0
+    :git: https://github.com/rileytestut/STPrivilegedTask.git
 
 SPEC CHECKSUMS:
   AltSign: c3693fa5a4b6d0ec6bedb74a5d768fe58bd67b87
@@ -43,8 +49,8 @@ SPEC CHECKSUMS:
   Nuke: 44130e95e09463f8773ae4b96b90de1eba6b3350
   Roxas: 1990039f843f5dc284918dc82375feb80020ef62
   Sparkle: 3f75576db8b0265adef36c43249d747f22d0b708
-  STPrivilegedTask: 103f97827454e786074640cf89d303be344498c7
+  STPrivilegedTask: 56c3397238a1ec07720fb877a044898373cd2c68
 
-PODFILE CHECKSUM: 467b50b42949f001543841f547fa6b427e29dc53
+PODFILE CHECKSUM: 1503b17048964bd0586d5470e6ee1e57917934de
 
 COCOAPODS: 1.8.4