replace assert.h with cassert

The former was deprecated with C++14.

According to the C++11 and C++17 standards, both files are identical.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

src/input/plugins/AlsaInputPlugin.cxx

@@ -43,7 +43,8 @@
 
 #include <alsa/asoundlib.h>
 
-#include <assert.h>
+#include <cassert>
+
 #include <string.h>
 
 static constexpr Domain alsa_input_domain("alsa");

src/input/plugins/CdioParanoiaInputPlugin.cxx

@@ -34,11 +34,12 @@
 #include "Log.hxx"
 #include "config/Block.hxx"
 
+#include <cassert>
+
 #include <stdio.h>
 #include <stdint.h>
 #include <string.h>
 #include <stdlib.h>
-#include <assert.h>
 
 #include <cdio/cd_types.h>
 

src/input/plugins/CurlInputPlugin.cxx

@@ -49,9 +49,9 @@
 #include "util/UriQueryParser.hxx"
 #endif
 
+#include <cassert>
 #include <cinttypes>
 
-#include <assert.h>
 #include <string.h>
 
 #include <curl/curl.h>

src/input/plugins/QobuzClient.cxx

@@ -21,10 +21,9 @@
 #include "lib/crypto/MD5.hxx"
 #include "util/ConstBuffer.hxx"
 
+#include <cassert>
 #include <stdexcept>
 
-#include <assert.h>
-
 namespace {
 
 class QueryStringBuilder {