pin pyobjc to fix dependency resolution issue

requirements.txt

@@ -15,7 +15,7 @@ pyserial>=3.5
 h5py>=3.1.0
 pytest-shutil
 pyo>=1.0.3; platform_system == "Linux"
-#keyboard requires pyobjc, psychopy requires version less than 8, setting pyobjc to
+#pynput requires pyobjc, psychopy requires version less than 8, setting pyobjc to
 # a specific version prevents dependency resolution deadlock.
 pyobjc==7.3; sys_platform == 'darwin'
 #Removed keyboard dependency due to using Carbon API not supported on Apple ARM64 chips, 
@@ -39,7 +39,7 @@ pyserial>=3.5
 h5py>=3.1.0
 pytest-shutil
 pyo>=1.0.3; platform_system == "Linux"
-#keyboard requires pyobjc, psychopy requires version less than 8, setting pyobjc to
+#pynput requires pyobjc, psychopy requires version less than 8, setting pyobjc to
 # a specific version prevents dependency resolution deadlock.
 pyobjc==7.3; sys_platform == 'darwin'
 #Removed keyboard dependency due to using Carbon API not supported on Apple ARM64 chips, 
@@ -54,7 +54,7 @@ click
 
 ## ~~ Stimpres Requirements ~~
 
-#keyboard requires pyobjc, psychopy requires version less than 8, setting pyobjc to
+#pynput requires pyobjc, psychopy requires version less than 8, setting pyobjc to
 # a specific version prevents dependency resolution deadlock.
 pyobjc==7.3; sys_platform == 'darwin'
 #upgrade psychopy to use newer wxpython dependency which is prebuilt for m1 support.