update IJPE source code

Author: frenkowski

IJPE_SCIMAI-Gym.ipynb

@@ -7685,7 +7685,7 @@
     "    \"\"\"\n",
     "    plt.figure(figsize=(8, 5))\n",
     "    plt.ylabel('Frequency')\n",
-    "    plt.xlabel('Cumulative Costs')\n",
+    "    plt.xlabel('Total Costs [k€]')\n",
     "\n",
     "    plt.tight_layout()\n",
     "\n",
@@ -7731,7 +7731,7 @@
     "    \"\"\"\n",
     "    plt.figure(figsize=(8, 5))\n",
     "    plt.ylabel('Frequency')\n",
-    "    plt.xlabel('MS-gap [%]')\n",
+    "    plt.xlabel('Opt-gap [%]')\n",
     "\n",
     "    plt.tight_layout()\n",
     "\n",