package/timescaledb: bump version to 2.20.0

Release notes: https://github.com/timescale/timescaledb/blob/2.20.0/CHANGELOG.md

Add the PG_PATH variable to ensure that CMake can find the "pg_config" program.
Otherwise, the following error will be reported.
CMake Error at CMakeLists.txt:85 (message):
  Unable to find 'pg_config'

Signed-off-by: Scott Fan <fancp2007@gmail.com>
Reviewed-by: Maxim Kochetkov <fido_max@inbox.ru>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/timescaledb/timescaledb.hash

@@ -1,3 +1,3 @@
 # Locally calculated
-sha256  ef2c9019f3e292f77e274a95386e550cb8c358ec0e053f6b7097565f61381e01  timescaledb-2.19.3.tar.gz
+sha256  b6ac4c29ef29e93249fcc25bf193dab2637422797360b12e00fd73067138a953  timescaledb-2.20.0.tar.gz
 sha256  0378e0948feefd85f579319c74d6e2b671194037f550c7176ef26649d94c895b  LICENSE

package/timescaledb/timescaledb.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-TIMESCALEDB_VERSION = 2.19.3
+TIMESCALEDB_VERSION = 2.20.0
 TIMESCALEDB_SITE = $(call github,timescale,timescaledb,$(TIMESCALEDB_VERSION))
 TIMESCALEDB_LICENSE = Apache-2.0
 TIMESCALEDB_LICENSE_FILES = LICENSE
@@ -23,6 +23,7 @@ TIMESCALEDB_CONF_OPTS = \
 	-DPG_PKGLIBDIR=lib/postgresql \
 	-DPG_SHAREDIR=share/postgresql \
 	-DPG_BINDIR=bin \
+	-DPG_PATH="$(STAGING_DIR)/usr" \
 	-DPG_CPPFLAGS="$(TARGET_CPPFLAGS) " \
 	-DPG_CFLAGS="$(TARGET_CFLAGS) " \
 	-DPG_LDFLAGS="$(TARGET_LDFLAGS) " \