Replace links to the documentation by the latest stable version

Author: migueldvb

tutorials/UVES/UVES.ipynb

@@ -457,12 +457,12 @@
       "Often, one has to keep track of the units for certain values. Was the wavelength\n",
       "given in Angstrom or in nm? In X-ray observations, a common unit of wavelength is\n",
       "keV. How many nm is 0.65 keV?\n",
-      "[`astropy.units`](http://docs.astropy.org/en/v0.2.1/units/index.html)\n",
+      "[`astropy.units`](http://docs.astropy.org/en/stable/units/index.html)\n",
       "offers a framework that can take\n",
       "care of this book-keeping and propagate the units through many (but not all)\n",
       "mathematical operations (e.g. addition, division, multiplication).\n",
       "Furthermore,\n",
-      "[`astropy.constants`](http://docs.astropy.org/en/v0.2.1/constants/index.html)  supplies the values of\n",
+      "[`astropy.constants`](http://docs.astropy.org/en/stable/constants/index.html)  supplies the values of\n",
       "many physical and astronomical constants.\n",
       "The easiest way to attach a unit to a number is by multiplication"
      ]
@@ -638,7 +638,7 @@
      "metadata": {},
      "source": [
       "I want to mention one more feature here (check out\n",
-      "[`astropy.units`](http://docs.astropy.org/en/v0.2.1/units/index.html) for\n",
+      "[`astropy.units`](http://docs.astropy.org/en/stable/units/index.html) for\n",
       "more): The ability to convert the spectral axis to frequencies or energies.\n",
       "Normally, a unit of length is not equivalent to a unit of energy or to a\n",
       "frequency, but this conversion makes sense for the wavelength of a spectrum.\n",
@@ -827,7 +827,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "[`astropy.time`](http://docs.astropy.org/en/v0.2.1/time/index.html\n",
+      "[`astropy.time`](http://docs.astropy.org/en/stable/time/index.html)\n",
       "provides methods to convert times and dates between different\n",
       "systems and formats. Since the ESO fits headers already contain the time of the\n",
       "observation in different systems, we could just read the keyword in the time\n",
@@ -1055,7 +1055,7 @@
       "Now, we want to generate a LaTeX table of the observation times, period\n",
       "and equivalent width that we can directly paste into our manuscript. To do so,\n",
       "we first collect all the columns and make an ``astropy.table.Table`` object. (Please\n",
-      "check [`astropy.table`](http://docs.astropy.org/en/v0.2.1/table/index.html)\n",
+      "check [`astropy.table`](http://docs.astropy.org/en/stable/table/index.html)\n",
       "or `tabular-data` for more\n",
       "details on ``Table``). So, here is the code"
      ]