fix(logging): "debug" messages not shown in "AWS Toolkit Logs" channel

Problem:
`vscode.LogOutputChannel` loglevel is currently readonly:
- microsoft/vscode#170450
- PowerShell/vscode-powershell#4441
So `debug()` will just drop messages unless the user has increased vscode's log-level.

Solution:
Write "debug" logs using `info()` until vscode adds a way to set the loglevel.

Author: justinmk3

src/shared/logger/outputChannelTransport.ts

@@ -64,7 +64,12 @@ export class OutputChannelTransport extends Transport {
                 } else if (loglevel === 'warn') {
                     c.warn(msg)
                 } else if (loglevel === 'debug' || loglevel === 'verbose') {
-                    c.debug(msg)
+                    // XXX: `vscode.LogOutputChannel` loglevel is currently readonly:
+                    //      https://github.com/microsoft/vscode/issues/170450
+                    //      https://github.com/PowerShell/vscode-powershell/issues/4441
+                    // So debug() will just drop messages unless the user has increased vscode's log-level.
+                    // Use info() until vscode adds a way to set the loglevel.
+                    c.info(msg)
                 } else {
                     c.info(msg)
                 }