Fix APCU_BC pecl extension generating errors upon install (#401)

* Fix APCU_BC generating errors
* Add upgrade file due to non-BC change

--------------------
Remove APCU_BC due to it generating errors. PECL `APC` now supports PHP 7.0+ as of version 5.1.0.

https://pecl.php.net/package/APCu

UPGRADE-2.0.md

@@ -0,0 +1,12 @@
+UPGRADE FROM 1.0.x to 2.0
+=======================
+
+### APCU_BC install
+
+  * Due to issues with the `apcu_bc` pecl extension install and [growing support for PHP 7.0+](https://pecl.php.net/package/APCu)
+  within the `apcu` pecl extension, deprecate the use of `apcu_bc`. To ensure new `apcu` install
+  do the following for every PHP version installed:
+
+      * Uninstall your pecl installed apcu extensions `pecl uninstall apcu && pecl uninstall apcu_bc`
+
+      * Remove the `apcu.so` and `apc.so` extensions from `/usr/local/etc/valet-php/<version>/php.ini`

cli/Valet/Pecl.php

@@ -47,15 +47,11 @@ class Pecl extends AbstractPecl
             'default' => false,
             'extension_type' => self::ZEND_EXTENSION_TYPE
         ],
-        self::APCU_BC_EXTENSION => [
-            '5.6' => false,
-            'extension_type' => self::NORMAL_EXTENSION_TYPE
-        ],
         self::APCU_EXTENSION => [
-            '7.3' => false,
-            '7.2' => false,
-            '7.1' => false,
-            '7.0' => false,
+            '7.3' => '5.1.17',
+            '7.2' => '5.1.17',
+            '7.1' => '5.1.17',
+            '7.0' => '5.1.17',
             '5.6' => '4.0.11',
             'extension_type' => self::NORMAL_EXTENSION_TYPE
         ],
@@ -264,9 +260,6 @@ private function removeIniDefinition($extension)
     private function alternativeDisable($extension)
     {
         switch ($extension) {
-            case self::APCU_BC_EXTENSION:
-                $this->disable(self::APCU_EXTENSION);
-                break;
             default:
                 break;
         }
@@ -284,10 +277,6 @@ private function alternativeDisable($extension)
     private function alternativeUninstall($extension)
     {
         switch ($extension) {
-            case self::APCU_BC_EXTENSION:
-                $version = $this->getVersion($extension);
-                $this->uninstall(self::APCU_EXTENSION, $version);
-                break;
             default:
                 break;
         }
@@ -462,8 +451,6 @@ public function isInstalled($extension)
     private function alternativeInstall($extension, $phpIniFile)
     {
         switch ($extension) {
-            case self::APCU_BC_EXTENSION:
-                return $this->replaceIniDefinition(self::APCU_EXTENSION, $phpIniFile);
             default:
                 return $phpIniFile;
         }
@@ -513,8 +500,6 @@ private function isDefaultExtension($extension)
     protected function getExtensionAlias($extension)
     {
         switch ($extension) {
-            case self::APCU_BC_EXTENSION:
-                return self::APCU_BC_ALIAS;
             default:
                 return $extension;
         }
@@ -566,8 +551,6 @@ private function isEnabledCorrectly($extension)
     private function isAlternativeEnabledCorrectly($extension)
     {
         switch ($extension) {
-            case self::APCU_BC_EXTENSION:
-                return $this->isEnabledCorrectly(self::APCU_EXTENSION);
             default:
                 return true;
         }